client API: fix terminal usage

By default this is disabled. But if it's enabled, then we have to
account for proper states when enabling/disabling the terminal state
itself.

player/main.c

@@ -142,8 +142,10 @@ void mp_destroy(struct MPContext *mpctx)
         ass_library_done(mpctx->ass_library);
 #endif
 
-    if (mpctx->opts->use_terminal)
+    if (mpctx->opts->use_terminal) {
         getch2_disable();
+        terminal_initialized = false;
+    }
     uninit_libav(mpctx->global);
 
     mp_msg_uninit(mpctx->global);
@@ -368,6 +370,7 @@ int mp_initialize(struct MPContext *mpctx)
     if (mpctx->opts->use_terminal && !terminal_initialized) {
         terminal_initialized = true;
         terminal_init();
+        mp_msg_update_msglevels(mpctx->global);
     }
 
     mpctx->input = mp_input_init(mpctx->global);