[lldb] [llvm] Remove hardware index from watchpoints and breakpoints (PR #72012)

[Jonas Devlieghere via llvm-commits]

https://github.com/JDevlieghere approved this pull request.

LGTM. I would've preferred to return something like `LLDB_INVALID_HARDWARE_INDEX` but as we're deprecating this, it doesn't seem worth adding another define for. 

https://github.com/llvm/llvm-project/pull/72012