[clang] Incorrect Microsoft mangling with auto and template type parameter

```c++
int z(int);
template
auto f() -> auto(*)(T) {
return z;
}
void g() { f();}
```

MSVC mangles this as `??$f@H@@YAP6A?A_PH@ZXZ`. clang produces `??$f@H@@YAP6A?A_P?@@ZXZ`. (Note the `` mangling is the fictitious mangling from #117845. CC @MaxEW707 .)

Possibly related to #203278 .

Start by compiling the provided C++ reproducer with Clang and comparing its Microsoft mangled name with the MSVC result. Trace Clang's Microsoft name-mangling handling for the dependent function-pointer return type, considering the related issue #203278. Done means the reproducer emits the expected MSVC mangling without the fictitious template-parameter encoding.

Written by the indexing model from the issue text.