When in grease pencil drawing mode, user could pin material or vertex
color to a specific brush or fill tool, but when switching tools, the
display and the logic of how those pinned material/vertex color are used
is inconsistent, leading to confusion.
The main cause of such problem is that the new GPv3 brush/fill tool is
not respecting pinning status, on top of that, user interface display
logic is also wrong. This PR makes sure that:
- Brush/fill tools respect pinning status.
- Buttons on the tool bar always display correct pinning status.
- Brush cursor will use correct color based on pinning status.
Pull Request: https://projects.blender.org/blender/blender/pulls/130968
fc2f815b66