component AP gateway: don't percent-encode @:

Mastodon doesn't like when "@" is percent-encoded (because it doesn't do it, and it checks
that the URL matches the ID without taking care of percent-encoding).

sat/plugins/plugin_comp_ap_gateway/__init__.py

@@ -838,7 +838,7 @@ class APGateway:
         """
         return parse.urljoin(
             self.base_ap_url,
-            str(Path(type_).joinpath(*(parse.quote_plus(a) for a in args)))
+            str(Path(type_).joinpath(*(parse.quote_plus(a, safe="@") for a in args)))
         )
 
     def isLocalURL(self, url: str) -> bool:

sat/plugins/plugin_comp_ap_gateway/http_server.py

@@ -592,7 +592,9 @@ class HTTPAPGServer(web_resource.Resource):
                 "https://w3id.org/security/v1"
             ],
 
-            "id": ap_url,
+            # XXX: Mastodon doesn't like percent-encode arobas, so we have to unescape it
+            #   if it is escaped
+            "id": ap_url.replace("%40", "@"),
             "type": "Person",
             "preferredUsername": preferred_username,
             "inbox": inbox,
@@ -637,7 +639,8 @@ class HTTPAPGServer(web_resource.Resource):
         return parse.urljoin(
             f"https://{self.apg.public_url}",
             request.path.decode().rstrip("/")
-        )
+        # we unescape "@" for the same reason as in [APActorRequest]
+        ).replace("%40", "@")
 
     def queryData2RSMRequest(
         self,