Add token to AppOptions so we can provide custom auth methods

[MehakBindra]

Minor change to allow users to pass their own token methods

For eg:

def create_token_factory():
    Create a token factory for authentication.
    async def get_token(scope: Union[str, List[str]], tenant_id: Optional[str] = None) -> str:
        managedIdentityCredential = ManagedIdentityCredential(
            client_id=os.getenv("CLIENT_ID")
        )
        scopes = [scope] if isinstance(scope, str) else scope
        token = managedIdentityCredential.get_token(*scopes, tenant_id=tenant_id)
        return token.token
    return get_token

app = App(token = create_token_factory())

[Copilot]

Pull Request Overview

This PR adds support for custom token authentication methods by introducing a new token field to the AppOptions configuration. This allows applications to provide their own token generation functions instead of relying solely on client credentials.

• Adds a token field to both AppOptions TypedDict and InternalAppOptions dataclass
• Updates the credential initialization logic to support TokenCredentials when a token function is provided
• Imports necessary types to support the new token callback function signature

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
packages/apps/src/microsoft/teams/apps/options.py	Adds token field definition and imports required types
packages/apps/src/microsoft/teams/apps/app.py	Implements token credential initialization logic and imports TokenCredentials

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[heyitsaamir]

LGTM, could you add a test, and a comment explaining what it is? I think we should probably also comment on all the AppOptions... but atleast start with this one :)