UI: revert changes to the unwrap menu in 4.3 based on user feedback

Move unwrapping operators from the "Unwrap" sub-menu back into
the top-level menu. Now pressing U twice unwraps as before.

Ref !132719

scripts/startup/bl_ui/space_image.py

@@ -401,7 +401,11 @@ class IMAGE_MT_uvs_unwrap(Menu):
     def draw(self, _context):
         layout = self.layout
 
-        layout.operator_enum("uv.unwrap", "method")
+        # It would be nice to do: `layout.operator_enum("uv.unwrap", "method")`
+        # However the menu items don't have an "Unwrap" prefix, so inline the operators.
+        layout.operator("uv.unwrap", text="Unwrap Angle Based").method = 'ANGLE_BASED'
+        layout.operator("uv.unwrap", text="Unwrap Conformal").method = 'CONFORMAL'
+        layout.operator("uv.unwrap", text="Unwrap Minimum Stretch").method = 'MINIMUM_STRETCH'
 
         layout.separator()
 

scripts/startup/bl_ui/space_view3d.py

@@ -1406,7 +1406,7 @@ class VIEW3D_MT_uv_map(Menu):
     def draw(self, _context):
         layout = self.layout
 
-        layout.menu("IMAGE_MT_uvs_unwrap")
+        layout.menu_contents("IMAGE_MT_uvs_unwrap")
 
         layout.separator()