[dotnet-linker] Remove the [DynamicDependency] parameter-list workaround once dotnet/runtime#131892 is fixed

[rolfbjarne]

Description

We work around dotnet/runtime#131892 (the trimmer crashes with a NullReferenceException, surfaced as error IL1012, when it computes the documentation signature of a method whose parameter type is a nested type from another assembly) by emitting [DynamicDependency] signatures without a parameter list whenever the method name (+ generic arity) is unambiguous within its declaring type.

The trimmer then matches the method by name and arity alone, so it never has to compute a parameter signature — and never crashes.

Once the trimmer bug is fixed (and we've moved to a version of the SDK that contains the fix), this workaround should be removed so that [DynamicDependency] attributes are precise again instead of preserving every overload.

Steps to reproduce

See dotnet/runtime#131892 for a self-contained repro.

What needs to be done

Location	What to do
tools/dotnet-linker/AppBundleRewriter.cs	Remove GetDynamicDependencySignature and go back to calling DocumentationComments.GetSignature directly in AddDynamicDependencyAttribute and AddDynamicDependencyAttributeToStaticConstructor.
tools/dotnet-linker/DocumentionComments.cs	Remove GetNameSignature if it ends up with no callers.
tests/assembly-preparer/PreserveBlockCodeHandlerTests.cs	Restore the Invoke(System.IntPtr,System.Int32) expectation.
tests/assembly-preparer/PreserveSmartEnumConversionsTest.cs	Restore the GetConstant(CoreAnimation.CAToneMapMode) expectation.
tests/dotnet/UnitTests/expected/*	Regenerate the expected app sizes (precise signatures preserve fewer members).

Note that AddPreserveAllMembersDynamicDependencyAttributes also uses GetNameSignature, but that one is intentional and should stay: it implements [Preserve (AllMembers = true)], where every overload is preserved anyway, so matching by name is both correct and cheaper.

Context

The workaround was added in #26410.