[clang] [clang][Sema] Diagnose exceptions only in non-dependent context in discarded `try/catch/throw` blocks (PR #139859)

[via cfe-commits]

cor3ntin wrote:

@Rajveer100 I think instead of looking at the context, we should check if the expression (`Ex`) is instantiation dependent

https://github.com/llvm/llvm-project/pull/139859