Add vtbls for IWeakReferenceSource and IWeakReference.

[jlaanstra]

Fixes ADO#41937903

When resolving an IWeakReference from a different context, we resolve as IUnknown and then assume that Resolve is the next method in the vtbl, see

CsWinRT/src/WinRT.Runtime/Interop/IWeakReferenceSource.net5.cs

Line 256 in 4182294

ExceptionHelpers.ThrowExceptionForHR((*(delegate* unmanaged[Stdcall]<IntPtr, Guid*, IntPtr*, int>**)ThisPtr)[3](ThisPtr, &riid, &objRef));

. This turns out to not be true and we end up calling an unrelated COM interface with incorrect parameters that than tries to allocate a very large array on the stack resulting in stack overflow.

[jlaanstra]

Superseded by #1301. Thanks @manodasanW