[clang] [analyzer] Fix crash in PaddingChecker on dependent field types (PR #232986)

[Manuel Sainz de Baranda y Goñi via cfe-commits]

redcode wrote:

Is this FIXME OK?

```c
void Sema::ActOnLambdaExpressionAfterIntroducer(LambdaIntroducer &Intro,
                                                Scope *CurrentScope) {
  /* ... */

  // Determine if we're within a context where we know that the lambda will
  // be dependent, because there are template parameters in scope.
  //
  // FIXME: A lambda in the noexcept specifier of an abbreviated function
  // template (e.g. `auto&&`) is not marked dependent, even though it captures
  // a dependent entity. Could this be because the implicit template parameter
  // is not in scope while the specifier is parsed, leaving the lambda's
  // dependency kind as LDK_Unknown?
  // See: https://github.com/llvm/llvm-project/issues/232874
```

<img width="692" height="525" alt="imagen" src="https://github.com/user-attachments/assets/efc6a4ca-88f0-4276-9357-6cc1fc9a5c9b" />

As for adding the `assert`... I just realized that the CI would then fail on this PR. Should this PR therefore remain open until another one is merged that fixes the bug in Sema?

https://github.com/llvm/llvm-project/pull/232986