[llvm] ci: Fix `pr-code-format` permissions for private forks (PR #120838)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

> In that case, should I create a patch that restricts the running of the action if: github.repository_owner == 'llvm' like it is done for many of the other workflow files?

Probably. It is worth checking the git history though as I remember some discussion about someone else removing it in a fork. I believe the consensus was that they should remove the check downstream, but I forget what ended up happening.

https://github.com/llvm/llvm-project/pull/120838