Use generic MethodInfo.CreateDelegate for explicitly cast delegates

Replace a resolved MethodInfo.CreateDelegate(typeof(T), optionalTarget) with CreateDelegate<T>(optionalTarget) when the same explicit delegate cast surrounds the call and all effective targets are .NET5+. Preserve receiver, target evaluation, type attribution and cast identity. Keep soft/mismatched casts, dynamic types, old language syntax, ambiguous owners, source shadows, comments, deferred contexts and conditional snapshots unchanged.