AI bug fixes and update interfaces (#6925)

* allow settings to load domain and user settings

* ensure engine is also enabled before attempting to create a new object

* add default values to stop undefined variable warnings

* enforce all models to set and return voices and languages

* enforce all models to set and return languages

* ensure speech_enabled is set by the current session

core/ai/resources/interfaces/ai_speech.php

@@ -8,6 +8,10 @@ if (!interface_exists('ai_speech')) {
 		public function set_format(string $audio_format);
 		public function set_voice(string $audio_voice);
 		public function set_message(string $audio_message);
+		public function get_voices() : array;
+		public function get_language_enabled() : bool;
+		public function set_language(string $audio_language);
+		public function get_languages() : array;
 		public function speech() : bool;
 	}
 }

core/ai/resources/interfaces/ai_transcribe.php

@@ -6,6 +6,8 @@ if (!interface_exists('ai_transcribe')) {
 		public function set_path(string $audio_path);
 		public function set_filename(string $audio_filename);
 		public function transcribe() : string;
+		public function set_language(string $audio_language);
+		public function get_languages() : array;
 	}
 }