GLTF: Change "Camera3D" generated node name to "Camera"

[aaronfranke]

This PR was originally a part of #80270, but fire requested that I split this out.

This string was originally "Camera" but was accidentally renamed to Camera3D during the 4.0 development cycle.

To be clear, this doesn't break compat any more than #80270 does. The names are already changed due to #80270. Before #80270 the names were like "Camera3D2", "Camera3D32", "Camera3D42", etc. As of #80270 they are "Camera3D", "Camera3D2", "Camera3D3", etc. With this PR the names are "Camera", "Camera2", "Camera3", etc. So the names are already changed, this PR just makes it more readable.

[akien-mga]

The camera node is named Camera3D in Godot 4, it seems sensible to me that we use the same convention for imported scenes, no?

[aaronfranke]

Node names do not necessarily need to match their type. In fact way back in 2019 I suggested having the editor instance nodes like "Camera3D" as just "Camera", but it was unpopular.

Anyway, if this one-line, two-character PR requires debate, I'm just going to close it. It's not important enough.

[lyuma]

I don't think this is worth the compatibility breakage.

If we are indeed breaking compat by changing node naming behavior in 4.2, I would prefer if somehow this node is always named "Camera" without a number after it. But that's neither here nor there.

[aaronfranke]

@lyuma I don't understand. Without this PR, there is already (very minor) compatibility breakage. Without this PR, the auto-generated nodes will never spit out a node named "Camera". It is here and there.

[lyuma]

Approved in meeting

[akien-mga]

Thanks!