Draft: Improvements to Filter Editor Dialog

• When a filter is duplicated in the Filter Editor, the name (label, or more specifically, inkscape:label) remains the same. So filter1 on duplicating would produce another filter with label filter1. With this fix, it changes the name to the previous name + _copy, or + _copy_1, or + _copy_n.
• Force update Filter Modifier's Filter List when XML change is received since the change could be in the filter labels.

New Behaviour:

Screencast_from_2024-03-17_01-46-49

• Allow User to Resize Panels in Filter Editor

Previous Behaviour:

Screencast_from_2024-03-17_20-20-25

New Behaviour:

Screencast_from_2024-03-17_20-13-58