UI: Make it possible to add shortcuts to UI operators.

Function `WM_keymap_guess_opname()` skipped `UI_OT` operator types. In
some cases this is detremental to workflow, see #105371.

To exclude operators from getting keyboard shortcut it was suggested by
Campbell to use flag `OPTYPE_INTERNAL` or make new one.

Pull Request: blender/blender#105383

source/blender/windowmanager/intern/wm_keymap_utils.c

@@ -183,7 +183,6 @@ wmKeyMap *WM_keymap_guess_opname(const bContext *C, const char *opname)
    *     ED_OT
    *     FLUID_OT
    *     TEXTURE_OT
-   *     UI_OT
    *     WORLD_OT
    */
 
@@ -446,6 +445,10 @@ wmKeyMap *WM_keymap_guess_opname(const bContext *C, const char *opname)
         break;
     }
   }
+  /* User Interface */
+  else if (STRPREFIX(opname, "UI_OT")) {
+    km = WM_keymap_find_all(wm, "User Interface", 0, 0);
+  }
 
   return km;
 }