Reflect now requires DynamicTypePath. Remove Reflect::get_type_path()

[cart]

Followup to #7184

This makes Reflect: DynamicTypePath which allows us to remove Reflect::get_type_path, reducing unnecessary codegen and simplifying Reflect implementations.

[cart]

It would be good to hear from @soqb on this just to make sure this doesn't break any scenarios they had in mind.
(although I can't personally imagine what it would break as these seem functionally equivalent)

[MrGVSV]

With the addition of #6971, it may also be worth considering how dynamic types should behave. Should they always return their own data or the data they represent? This is the reason we have Reflect::get_represented_type_info return an Option<&'static TypeInfo>.

My current take is that we should always return the values for the dynamic type itself and not what it represents. We already have TypeInfo for that purpose (we may even consider storing this information on TypeInfo as well). Additionally, DynamicTypePath wouldn't even be able to handle that anyways since it's a trait.

But anyway, I think this makes sense and makes using these methods a little simpler.

[soqb]

this certainly looks like a straightforward improvement and i agree with @MrGVSV that the implementation should be valid for the dynamic types themselves and not what they represent.

it's left me a little confused as to why we need Reflect::as_any but not Reflect::get_type_path, though.

edit: now wondering if we wouldn't just be able to impose a Reflect: TypePath bound. because it would violate object safety!