Save backlight color setting

applications/main/xtreme_app/scenes/xtreme_app_scene_misc.c

@@ -40,6 +40,7 @@ static void xtreme_app_scene_misc_lcd_color_changed(VariableItem* item) {
     uint8_t index = variable_item_get_current_value_index(item);
     variable_item_set_current_value_text(item, rgb_backlight_get_color_text(index));
     rgb_backlight_set_color(index);
+    app->save_backlight = true;
     notification_message(app->notification, &sequence_display_backlight_on);
 }
 

applications/main/xtreme_app/xtreme_app.c

@@ -114,6 +114,10 @@ static bool xtreme_app_back_event_callback(void* context) {
             furi_record_close(RECORD_DOLPHIN);
         }
 
+        if(app->save_backlight) {
+            rgb_backlight_save_settings();
+        }
+
         if(app->save_settings) {
             XTREME_SETTINGS_SAVE();
         }

applications/main/xtreme_app/xtreme_app.h

@@ -62,6 +62,7 @@ typedef struct {
     bool save_subghz;
     bool save_name;
     bool save_level;
+    bool save_backlight;
     bool save_settings;
     bool require_reboot;
 } XtremeApp;

firmware/targets/f7/api_symbols.csv

@@ -2525,7 +2525,7 @@ Function,+,rgb_backlight_get_color_count,uint8_t,
 Function,+,rgb_backlight_get_color_text,const char*,uint8_t
 Function,+,rgb_backlight_get_settings,RGBBacklightSettings*,
 Function,-,rgb_backlight_load_settings,void,
-Function,-,rgb_backlight_save_settings,void,
+Function,+,rgb_backlight_save_settings,void,
 Function,+,rgb_backlight_set_color,void,uint8_t
 Function,-,rgb_backlight_update,void,uint8_t
 Function,-,rindex,char*,"const char*, int"