[llvm] workflows/build-ci-container: Fix container push (PR #125610)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 commented:

Have you tested this outside of the PR?

It would be nice if we could figure out a better way to test this. I've definitely caused issues with this before and it's a major detriment that we aren't able to test this before merging. I'll have to see if I can cook something up when I have more time.

https://github.com/llvm/llvm-project/pull/125610