Fix T93169: Weightpaint falloff popover drawn twice

This came with {rBf8a0e102cf5e}.

The panel was meant specifically for the gradient tool, but since it was
given the ".weighpaint" context, it would also draw as part of generic
header toolsettings drawing.

Now remove this context on purpose and only draw this specifically from
the gradient tools ToolDef.

Maniphest Tasks: T93169

Differential Revision: https://developer.blender.org/D13268

release/scripts/startup/bl_ui/space_view3d_toolbar.py

@@ -689,7 +689,9 @@ class VIEW3D_PT_tools_brush_stroke_smooth_stroke(Panel, View3DPaintPanel, Smooth
 
 
 class VIEW3D_PT_tools_weight_gradient(Panel, View3DPaintPanel):
-    bl_context = ".weightpaint" # dot on purpose (access from topbar)
+    # dont give context on purpose to not show this in the generic header toolsettings
+    # this is added only in the gradient tool's ToolDef
+    #bl_context = ".weightpaint" # dot on purpose (access from topbar)
     bl_label = "Falloff"
     bl_options = {'DEFAULT_CLOSED'}