[clang-tools-extra] [clang-tidy] Add a new check 'bugprone-redundant-string-view-conversions' (PR #174288)

[Zinovy Nis via cfe-commits]

irishrover wrote:

- New cases handled
- Much more tests added
- The matcher code was commented (thanks to Claude for saving my time)
- Renamed to performance-string-view-conversions?

https://github.com/llvm/llvm-project/pull/174288