fix: misc-use-internal-linkage warnings (#44872)

* refactor: fix misc-use-internal-linkage warnings:

move impl functions into anonymous namespace so that they're not visible
to other compilation units

shell/browser/api/electron_api_menu.cc

@@ -70,6 +70,8 @@ Menu::~Menu() {
   }
 }
 
+namespace {
+
 bool InvokeBoolMethod(const Menu* menu,
                       const char* method,
                       int command_id,
@@ -84,6 +86,8 @@ bool InvokeBoolMethod(const Menu* menu,
   return gin::ConvertFromV8(isolate, val, &ret) ? ret : default_value;
 }
 
+}  // namespace
+
 bool Menu::IsCommandIdChecked(int command_id) const {
   return InvokeBoolMethod(this, "_isCommandIdChecked", command_id);
 }