Fix: Grease pencil vertex paint brush tool not showing

b64bf66257 changed how brush based tools are defined. It was authored
before the vertex paint tools got added back for grease pencil v3, so
this additional change was missing.

scripts/startup/bl_ui/space_toolsystem_toolbar.py

@@ -2877,26 +2877,6 @@ class _defs_grease_pencil_vertex:
             )
         )
 
-    @staticmethod
-    def generate_from_brushes(context):
-        # Though `data_block` is conceptually unnecessary with a single brush tool,
-        # it's still used because many areas assume that brush tools have it set #bToolRef.
-        tool = None
-        if context:
-            brush = context.tool_settings.gpencil_vertex_paint.brush
-            if brush:
-                tool = brush.gpencil_vertex_tool
-        return [
-            ToolDef.from_dict(
-                dict(
-                    idname="builtin.brush",
-                    label="Brush",
-                    icon="brush.sculpt.paint",
-                    data_block=tool
-                )
-            )
-        ]
-
 
 class _defs_curves_sculpt:
     # No mode specific tools currently (only general ones).
@@ -3743,7 +3723,7 @@ class VIEW3D_PT_tools_active(ToolSelectPanelHelper, Panel):
             ),
         ],
         'VERTEX_GREASE_PENCIL': [
-            _defs_grease_pencil_vertex.generate_from_brushes,
+            _brush_tool,
             None,
             *_tools_annotate,
             None,