[3.x] Fix OccluderPolyShape handles disappear after release click

[timothyqiu]

Fixes #79939

Also checked the 4.0 version. The problem was fixed by replacing this special logic with reworking the EditorPlugin editing logic ;) Since this code is intended to deselect when non-Spatial node is selected, excluding Resource here makes sense.

[lawnjelly]

Just to note, as I understand it:

According to the naming EditorSpatialGizmo the old behaviour kind of makes sense (and was understandable to add). The difficulty is that when editing spatial resources, there's no point duplicating all the functionality which already exists for spatials, so this was reused for the occluder shape resources (there's also a historical element here, they were originally spatials, but then changed to resources as it made more sense for sharing data).

There could also be alternative ways of querying whether something is meant to activate this logic (e.g. a virtual function) if finer grain was needed.

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.5.3. (Together with #80197.)