MT#61856 media_player: use `str_free()` for cached file keys

`media_player_media_files_insert()` stores keys allocated
with `str_dup()`, but during the eviction,
the key is freed with `g_free()`. Use `str_free()` instead.

Change-Id: I17a8498f7cf850a3cc2015130d1aa689f3f7c553

daemon/media_player.c

@@ -2495,7 +2495,7 @@ static bool __media_player_evict_file(str *name) {
 	}
 
 	obj_put(val);
-	g_free(key);
+	str_free(key);
 
 	return true;
 }