remove @staticmethod decorators

There might have been a time when calling a static method was faster
than a regular method, but that is no longer the case. According to
micro-benchmarks, it is 70% slower in CPython 3.13 and it also makes
executing the code of a class definition slower.

gallery_dl/extractor/8muses.py

@@ -92,8 +92,7 @@ class _8musesAlbumExtractor(Extractor):
                 album["updatedAt"], "%Y-%m-%dT%H:%M:%S.%fZ"),
         }
 
-    @staticmethod
-    def _unobfuscate(data):
+    def _unobfuscate(self, data):
         return util.json_loads("".join([
             chr(33 + (ord(c) + 14) % 94) if "!" <= c <= "~" else c
             for c in text.unescape(data.strip("\t\n\r !"))