Change in updateUser mutation

[Nikhilh26]

What kind of change does this PR introduce? Earlier API wasnt allowing user to update their own information now these changes allow users to update their info and admin to update every users info

Issue Number: This is required for the following issue Fixes (https://github.com/PalisadoesFoundation/talawa-admin/pull/3599)

Snapshots/Videos:

If relevant, did you update the documentation?

Summary

Does this PR introduce a breaking change?

Checklist

CodeRabbit AI Review

• [ ] I have reviewed and addressed all critical issues flagged by CodeRabbit AI
• [ ] I have implemented or provided justification for each non-critical suggestion
• [ ] I have documented my reasoning in the PR comments where CodeRabbit AI suggestions were not implemented

Test Coverage

• [ ] I have written tests for all new changes/features
• [ ] I have verified that test coverage meets or exceeds 95%
• [ ] I have run the test suite locally and all tests pass

Other information

Have you read the contributing guide?

Summary by CodeRabbit

• New Features

  • Regular users can now update their own profile information, enhancing personal data management.

• Bug Fixes

  • Improved validation and error messaging now clearly inform users when attempting to perform unauthorized changes, such as modifying another user's details or updating a non-existent account.