[llvm] [lldb] Add lldb team to CODEOWNERS (PR #65454)

[David Spickett via llvm-commits]

DavidSpickett wrote:

The warning isn't shown for [pr-subscribers-x86](https://github.com/orgs/llvm/teams/pr-subscribers-x86) so there's something different about the lldb team.

https://github.com/llvm/llvm-project/pull/65454