[5.6] Handle unquoted JSON selector for MYSQL

[chrishubert]

I propose the wrapper to handle unquoted output (using ->> : reference )
The unquoted result is easier to digest later on.

Originally PaymentMethod::select(['id', 'settings->>name'])->get(); would output

#attributes: array:2 [▼
    "id" => "1"
    "`settings`->'$.">name"'" => null
]

NowPaymentMethod::select(['id', 'settings->>name'])->get(); will output

#attributes: array:2 [▼
    "id" => "1"
    "`settings`->>'$."name"'" => "Bank transfer"
]

[sisve]

This looks like something that could use a test.

[chrishubert]

@sisve - Test added

[chrishubert]

It's actually interesting - the function wrapJsonSelector in PostgresGrammar by default return an unquoted version 🤔