Restart action doesn't run session start

[erohmensing]

Rasa version:
master

Issue:
If you restart a conversation using /restart (or call the Restarted() event from your actions), neither the restart action nor the restarted event call the session start action/event. This leads to a different context when starting a conversation via the webhook or server start and in the middle of the conversation. I would expect that restart would recreate the state of a new conversation.

Debug logs on new conversation:

Bot loaded. Type a message and press enter (use '/stop' to exit):
Your input ->  hi
2020-06-08 13:55:46 DEBUG    rasa.core.tracker_store  - Creating a new tracker for id '1beb4433a0db47ec8d9a57ad55125a6f'.
2020-06-08 13:55:46 DEBUG    rasa.core.processor  - Starting a new session for conversation ID '1beb4433a0db47ec8d9a57ad55125a6f'.
2020-06-08 13:55:46 DEBUG    rasa.core.actions.action  - Calling action endpoint to run action 'action_session_start'.
2020-06-08 13:55:48 DEBUG    rasa.core.processor  - Action 'action_session_start' ended with events '[<rasa.core.events.SessionStarted object at 0x15ddd1f50>, <rasa.core.events.SlotSet object at 0x15dde50d0>, <rasa.core.events.SlotSet object at 0x15dde5090>, <rasa.core.events.SlotSet object at 0x15dde5110>, <rasa.core.events.SlotSet object at 0x15dde5250>, <rasa.core.events.SlotSet object at 0x15dde5190>, <rasa.core.events.SlotSet object at 0x15dde5210>, <rasa.core.events.ActionExecuted object at 0x15dde51d0>]'.
2020-06-08 13:55:48 DEBUG    rasa.core.processor  - Current slot values:
	PERSON: None
	account_balance: 6630.64
	amount_of_money: None
	amount_transferred: 0
	confirm: None
	credit_card: None
	credit_card_balance: {'iron bank': {'minimum balance': 20, 'current balance': 258.08}, 'credit all': {'minimum balance': 20, 'current balance': 203.94}, 'gringots': {'minimum balance': 20, 'current balance': 329.68}, 'justice bank': {'minimum balance': 20, 'current balance': 296.47}}
	currency: $
	end_time: None
	grain: None
	known_recipients: ['emma', 'evan', 'william', 'karen', 'kyle', 'john', 'percy', 'lisa']
	payment_amount: None
	payment_amount_type:
	requested_slot: None
	search_type: None
	start_time: None
	time: None
	transaction_history: {'spend': {'target': [{'amount': 29.94, 'date': '2019-04-14'}, {'amount': 38.83, 'date': '2019-11-20'}], 'starbucks': [{'amount': 17.57, 'date': '2020-03-23'}, {'amount': 16.05, 'date': '2019-07-18'}], 'amazon': [{'amount': 7.22, 'date': '2020-02-14'}, {'amount': 33.65, 'date': '2019-09-25'}]}, 'deposit': {'employer': [{'amount': 1404.49, 'date': '2019-02-27'}, {'amount': 1148.78, 'date': '2019-06-07'}, {'amount': 1009.92, 'date': '2019-05-12'}, {'amount': 1333.77, 'date': '2019-02-20'}], 'interest': [{'amount': 1876.94, 'date': '2019-11-07'}]}}
	vendor_list: ['target', 'starbucks', 'amazon']
	vendor_name: None

Debug logs after sending /restart:

Hi, how can I help you?
Your input ->  /restart
2020-06-08 13:56:17 DEBUG    rasa.core.tracker_store  - Recreating tracker for id '1beb4433a0db47ec8d9a57ad55125a6f'
2020-06-08 13:56:17 DEBUG    rasa.core.processor  - Received user message '/restart' with intent '{'name': 'restart', 'confidence': 1.0}' and entities '[]'
2020-06-08 13:56:17 DEBUG    rasa.core.processor  - Logged UserUtterance - tracker now has 14 events.
2020-06-08 13:56:17 DEBUG    rasa.core.policies.fallback  - NLU confidence threshold met, confidence of fallback action set to core threshold (0.3).
2020-06-08 13:56:17 DEBUG    rasa.core.policies.memoization  - Current tracker state [None, {}, {'prev_action_listen': 1.0, 'intent_greet': 1.0}, {'prev_utter_greet': 1.0, 'intent_greet': 1.0}, {'prev_action_listen': 1.0, 'intent_restart': 1.0}]
2020-06-08 13:56:17 DEBUG    rasa.core.policies.memoization  - Launch DeLorean...
2020-06-08 13:56:17 DEBUG    rasa.core.policies.memoization  - Current tracker state [None, None, None, {}, {'prev_action_listen': 1.0, 'intent_restart': 1.0}]
2020-06-08 13:56:17 DEBUG    rasa.core.policies.memoization  - There is no memorised next action
2020-06-08 13:56:17 DEBUG    rasa.core.policies.form_policy  - There is no active form
2020-06-08 13:56:17 DEBUG    rasa.core.policies.mapping_policy  - The predicted intent 'restart' is mapped to  action 'action_restart' in the domain.
2020-06-08 13:56:17 WARNING  rasa.core.featurizers  - Feature 'intent_restart' could not be found in feature map.
2020-06-08 13:56:17 DEBUG    rasa.core.policies.ensemble  - Predicted next action using policy_3_MappingPolicy
2020-06-08 13:56:17 DEBUG    rasa.core.processor  - Predicted next action 'action_restart' with confidence 1.00.
2020-06-08 13:56:17 DEBUG    rasa.core.processor  - Action 'action_restart' ended with events '[<rasa.core.events.Restarted object at 0x1718e0f10>]'.
2020-06-08 13:56:17 DEBUG    rasa.core.processor  - Current slot values:
	PERSON: None
	account_balance: None
	amount_of_money: None
	amount_transferred: 0
	confirm: None
	credit_card: None
	credit_card_balance: None
	currency: None
	end_time: None
	grain: None
	known_recipients: None
	payment_amount: None
	payment_amount_type:
	requested_slot: None
	search_type: None
	start_time: None
	time: None
	transaction_history: None
	vendor_list: None
	vendor_name: None
2020-06-08 13:56:17 DEBUG    rasa.core.processor  - Predicted next action 'action_listen' with confidence 1.00.
2020-06-08 13:56:17 DEBUG    rasa.core.processor  - Action 'action_listen' ended with events '[]'.
2020-06-08 13:56:17 DEBUG    rasa.core.lock_store  - Deleted lock for conversation '1beb4433a0db47ec8d9a57ad55125a6f'.

[stale]

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