Refactor: Replace deprecated CurrentUserProviderOld with CurrentUserProvider

[Nishargo]

Summary

Multiple files across the codebase still use the deprecated CurrentUserProviderOld interface. The compiler warns on every build: 'interface CurrentUserProviderOld : Any' is deprecated.
Use CurrentUserProvider instead.

Affected files

See build warnings.

Proposed solution

Replace all usages of CurrentUserProviderOld with CurrentUserProvider across the affected files and remove CurrentUserProviderOldImpl once no longer referenced.

Notes

Happy to work on this if the maintainers are open to it. Could be done file by file in separate PRs to keep changes
reviewable, or in one larger refactor PR; whatever the team prefers.

[mahibi]

Yes i marked CurrentUserProviderOld as deprecated. Feel free to replace the usages with CurrentUserProvider.
Please keep the PR's small, so file by file will be appreciated.

Thank you for contributing 👍