[Engineering] Lower time for BotBuilder-core tests

[ceciliaavila]

Address #2338

Description

This pull request updates tests in the BotBuilder-Core library to remove unused variables, re-arrange resources, and remove duplicated tests to reduce time.

Specific Changes

autoSaveStateMiddleware.test.js:

• Moved reusable variables fooState and barState instead of creating them for each test.
• Fixed eslint warnings.

botState.test.js:

• Removed superfluous test.
• Fixed eslint warnings.

conversationState.test.js:

• Removed unused endOfConversation variable.
• Fixed eslint warnings.

memoryStorage.test.js:

• Removed unnecessary storage variable already parsed when using testStorage function. The default is never used as it already parse a new MemoryStorage in line 74.

memoryTranscriptStore.test.js:

• Moved storage variable to be reused.
• Fixed eslint warnings.

privateConversationState.test.js:

• Removed unused endOfConversation variable.
• Removed unnecessary key variable declaration.
• Fixed eslint warnings.

showTypingMiddleware.test.js:

• Remove unused receivedMessage variable.
• Fixed eslint warnings.

testAdapter.test.js:

• Removed unused start variable in multiple tests.
• Fixed eslint warnings.

Testing

As you see in the next images, the time for the tests decreased approximately 1 second and the code coverage did not decrease.