[clang] [Clang] prevent recovery call expression from proceeding with explicit attributes and undeclared templates (PR #107786)

[Erich Keane via cfe-commits]

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

Diag seems reasonable to me now.  I want Aaron to take another look (he's sadly out this week, so it'll have to be when he gets back), but I think this seems to make sense here.

https://github.com/llvm/llvm-project/pull/107786