[5.x] Adds support for configuring Access Scope for providers from configuration

[TheAladeen]

Hi All,

Description

This PR adds support for easily adding Access Scopes for 0Auth Providers by specifying the scopes key in the application's config/services.php as shown below:

    'github' => [
        'client_id'     => env('GITHUB_CLIENT_ID'),
        'client_secret' => env('GITHUB_CLIENT_SECRET'),
        'redirect'      => env('GITHUB_REDIRECT_URI'),
        'scopes'        => ['read:user', 'user:email'],
    ],

Specified scopes are merged with the scopes already defined in the provider's class to ensure appropriate scopes are still submitted.

Tests written for default implementation and implementation with additional provided scopes.

End User Benefits

Instead of needing to alter the default implementation as described in The Official Documentation, users can simply add an array key to their configuration for the same affect.

Existing Features Considerations and Technical Notes

Updated SocialiteManager->buildProvider to initialise scopes from the configuration services.{driver}.scopes array if provided.

Added tests to validate GitHub driver behaves correctly with and without services.{driver}.scopes array provided.

Ensured scopes are returned as indexed arrays without missing indexes by using array_values to prevent possible future implementation issues.

Ensure backwards compatibility by wrapping provider instantiation in parenthesis when calling AbstractProvider->scopes() in SocialiteManager->buildProvider().