[llvm] workflows/release-binaries: Always pull composite actions from main branch (PR #100805)

[Tom Stellard via llvm-commits]

tstellar wrote:

Should have looked closer, the test failure didn't show up in the checks list, I think because there was a bug in the yml.  I'll push a fix-up commit.

https://github.com/llvm/llvm-project/pull/100805