[clang] [clang-format] Fix crash involving array designators and dangling comma (PR #77045)

[via cfe-commits]

XDeme wrote:

While I was trying to find a minimal reproducer to the bug, I accidentally found that this patch fix another crash, and doesn't fix the linked issue.
What should be done here?


https://github.com/llvm/llvm-project/pull/77045