Fix Godot 4.1 errors

[limbonaut]

Fixes issues with _parse_property signature in Godot 4.1 while preserving backwards compatibility. Also fixes lack of theming in "Make Unique" dialog.

Error messages that this PR fixes

``` res://addons/rmsmartshape/editors/action_property_inspector_plugin.gd:41 - Parse Error: The function signature doesn't match the parent. Parent signature is "_parse_property(Object, Variant.Type, String, PropertyHint, String, int, bool) -> bool". res://addons/rmsmartshape/editors/normal_range_inspector_plugin.gd:32 - Parse Error: The function signature doesn't match the parent. Parent signature is "_parse_property(Object, Variant.Type, String, PropertyHint, String, int, bool) -> bool". ```

Testing

While under review, my PRs (#118, #123 and #126) are available merged in this branch: https://github.com/limbonaut/SmartShape2D/tree/integration

[limbonaut]

Should resolve #124

[naturally-intelligent]

Tested on my projects, looks good

[asciifaceman]

Fixed the errors for me. Implemented by hand locally.