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

[Tom Stellard via llvm-commits]

tstellar wrote:

I haven't tested this change yet, but I did test the previous change here: https://github.com/tstellar/llvm-project/actions/runs/13066122003/job/36458752114 It didn't fail on my fork though, I think due to some permissions differences.

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