Feature: Implement Update User Details API (`POST /api/users/:userId`)

[MessiasLima]

Feature: Implement Update User Details API (POST /api/users/:userId)

Background

This feature involves implementing the POST /api/users/:userId endpoint from the Umami API within the umami-kotlin library. This endpoint allows an authenticated user, typically an administrator or the user themselves, to update specific details for a user identified by userId. The request body will contain the fields to be updated.

Implementing this functionality is crucial for providing comprehensive user management capabilities within the umami-kotlin client. It will enable applications to modify user profiles, manage user roles, and update other user-specific information programmatically. This work directly contributes to fulfilling the "Umami API" section of the project roadmap, enhancing user-related functionalities.

Acceptance criteria

• GIVEN the Umami client is configured with a valid baseUrl and an authenticated user with appropriate permissions (e.g., an administrator, or the user whose ID matches :userId),
  WHEN a request is made to update details for a specific userId with valid new data via a new API method (e.g., umami.users.updateUserDetails(userId, updateData)),
  THEN the client successfully sends a POST request to /api/users/:userId with the update data
  AND the method returns a successful response indicating the user details have been updated.
• GIVEN the Umami client is configured with a valid baseUrl and an authenticated user,
  WHEN a request is made to update details for a userId for which the authenticated user lacks permissions,
  THEN the client successfully sends a POST request to /api/users/:userId
  AND the method returns an error response (or throws an appropriate UmamiAuthException or UmamiPermissionException) indicating access is denied.
• GIVEN the Umami client is configured with a valid baseUrl and an authenticated user with permissions,
  WHEN a request is made to update details for a userId that does not exist or with invalid update data (e.g., incorrect format, missing required fields),
  THEN the client successfully sends a POST request to /api/users/:userId
  AND the method returns an error response (or throws an appropriate UmamiNotFoundException or UmamiValidationException) indicating the failure.
• GIVEN the Umami client is configured,
  WHEN a request is made to update user details and a network or server error occurs during the API call,
  THEN the new API method throws an appropriate exception (e.g., IOException, UmamiApiException).
• GIVEN the umami-kotlin library is used in a project,
  WHEN a developer initializes the Umami client using Umami.create(),
  THEN the Umami instance exposes a public method (e.g., umami.users.updateUserDetails(userId: String, updateData: UserUpdateRequest)) to interact with the POST /api/users/:userId endpoint.