Unclear usage of overrideSignInActivity

overrideSignInActivity?: (
tokenExchangeResource?: TokenExchangeResource,
tokenPostResource?: TokenPostResource,
signInLink?: string
) => ActivityLike; in https://github.com/microsoft/teams.ts/blob/fb646c421851bcf59c7090f48ed3f0b89e621bf4/packages/apps/src/contexts/activity.ts#L114 will lead user to believe that they cannot customize tokenExchangeResource, tokenPostResource and signInLink but can only process these values after receiving it.

Would be better if we could make it clear or adding some docs around it.

Start at packages/apps/src/contexts/activity.ts around line 114 and read the overrideSignInActivity type and its surrounding context. Clarify in the API text or nearby documentation whether tokenExchangeResource, tokenPostResource, and signInLink can be customized, and ensure the resulting usage guidance matches the declared behavior.

Written by the indexing model from the issue text.