[llvm] [bazel] Update to 7.x (PR #86297)

[Aaron Siddhartha Mondal via llvm-commits]

https://github.com/aaronmondal approved this pull request.

Cool! I'll also take another look at https://github.com/llvm/llvm-project/issues/55924.

https://github.com/llvm/llvm-project/pull/86297