Can't set properties that are present but not set in the editor theme

[leogott]

Certain properties can't be set with ThemeGen, because they are not set / null in the default theme. So has_... fails and Item type can't be inferred for those.
Two examples are icon and hover_pressed for the Button

--- Debugging process stopped ---
  core/variant/variant_utility.cpp:1092 - Item name 'hover_pressed' not recognized for type 'Button'.
  core/variant/variant_utility.cpp:1092 - Item name 'icon' not recognized for type 'Button'.
=== ThemeGen v1.1 by Inspiaaa ===
[ThemeGen] Discovered 1 theme(s).
--- EditorScript(my_theme.gd)::setup ---
[ThemeGen] Setting up theme generation.... (EditorScript(my_theme.gd)::setup)
[ThemeGen] Generating theme... (EditorScript(my_theme.gd)::define_theme)
[ThemeGen] Loading default font...
[ThemeGen] Loading variants...
[ThemeGen] Loading styles...
[ThemeGen] > Style 'Button':
[ThemeGen]   > Preprocessing...
[ThemeGen]   > Loading...
[ThemeGen] Theme generation finished.
---
===

ThemeGen v1.1
Godot 4.3-stable