refactor: remove legacy fallback for mobile: getAppStrings

This change removes the legacy fallback mechanism when executing
`mobile: getAppStrings` in `appium/webdriver/extensions/applications.py`.
The `app_strings` method now exclusively uses the `execute_script`
approach.

Correspondingly, the `GET_APP_STRINGS` command registration in
`Applications._add_commands` and the command definition in
`MobileCommand` have also been removed.

Author: Dor-bl

appium/webdriver/extensions/applications.py

@@ -241,11 +241,7 @@ def app_strings(self, language: Union[str, None] = None, string_file: Union[str,
             data['language'] = language
         if string_file is not None:
             data['stringFile'] = string_file
-        try:
-            return self.assert_extension_exists(ext_name).execute_script(ext_name, data)
-        except UnknownMethodException:
-            # TODO: Remove the fallback
-            return self.mark_extension_absence(ext_name).execute(Command.GET_APP_STRINGS, data)['value']
+        return self.assert_extension_exists(ext_name).execute_script(ext_name, data)
 
     def _add_commands(self) -> None:
         self.command_executor.add_command(Command.BACKGROUND, 'POST', '/session/$sessionId/appium/app/background')
@@ -271,4 +267,3 @@ def _add_commands(self) -> None:
             'POST',
             '/session/$sessionId/appium/device/app_state',
         )
-        self.command_executor.add_command(Command.GET_APP_STRINGS, 'POST', '/session/$sessionId/appium/app/strings')

appium/webdriver/mobilecommand.py

@@ -31,7 +31,6 @@ class MobileCommand:
     SWITCH_TO_CONTEXT = 'switchToContext'
 
     BACKGROUND = 'background'
-    GET_APP_STRINGS = 'getAppStrings'
 
     IS_LOCKED = 'isLocked'
     LOCK = 'lock'