Game crashes when adding color preset after clearing presets in another control

[FeniXb3]

Tested versions

• Reproducible in: 4.4 (and previous 4.4.dev builds since saving color palettes was introduced Save color palette as resources to reuse later #91604)

System information

Godot v4.4.stable - Windows 11 (build 26100) - Multi-window, 1 monitor - Vulkan (Forward+) - integrated AMD Radeon 780M Graphics (Advanced Micro Devices, Inc.; 32.0.11039.8001) - AMD Ryzen 7 8845HS w/ Radeon 780M Graphics (16 threads)

Issue description

If you have multiple ColorPickers in the scene and one ColorPicker uses saved color palette and it was cleared, trying to add color preset in another ColorPicker, if that color was added to the presets before, it would crash the game.

Nagrywanie.ekranu.2025-03-16.100359.mp4

Steps to reproduce

1. Add 2 or more ColorPickers to the scene
2. Assign different colors to each ColorPicker
3. Run the game
4. Open Swatches in each ColorPicker and add current color to presets
5. Save presets of one ColorPicker as color palette (you will see another issue mentioned in Wrong color presets displayed after saving color palette with multiple ColorPickers in the scene #104223)
6. Clear presets in the ColorPicker that you saved the palette in
7. In another ColorPicker press the button to add current color to presets without chaning the color before (it should be the same color, as was added to presets for this ColorPicker before
8. The game should crash

Minimal reproduction project (MRP)

regression-test-project.zip