[Tracking Issue]: Leverage Rust diagnostics attributes to improve "type-checking" related error messages

[davidsemakula]

Use Rust's #[diagnostic::on_unimplemented(...)] and #[diagnostic::do_not_recommend] attributes to improve diagnostics messages for ink!'s "internal" "type-checking" abstractions

• Use the diagnostic attributes on "internal" traits that are only used for "type-checking" where an error telling the user about a missing trait implementation is not very useful
  • ConstructorOutput
  • ConstructorReturnType
  • ...
• Convert some type-checking "guards" that are currently struct-based into trait-based ones to improve their error messages in a similar way
  • DispatchInput
  • DispatchOutput
  • DispatchInputSol
  • DispatchOutputSol
  • ...

See #2722 for an example of leveraging these attributes to improve diagnostics messages