[llvm] [llvm] [cmake] Expose `LLVM_BUILD_TELEMETRY` in `LLVMConfig.cmake` (PR #126710)

[James Henderson via llvm-commits]

https://github.com/jh7370 commented:

Looks reasonable to me, but I'll leave it to an LLDB developer to approve, since they'll be better able to confirm this fixes the issue.

https://github.com/llvm/llvm-project/pull/126710