Don't pass token into AvatarGitHub, it works perfectly without it

Signed-off-by: magic_rb <richard@brezak.sk>

buildbot_nix/github_projects.py

@@ -650,22 +650,7 @@ class GithubBackend(GitBackend):
         }
 
     def create_avatar_method(self) -> AvatarBase | None:
-        avatar = AvatarGitHub(token=self.auth_backend.get_general_token().get())
-
-        # TODO: not a proper fix, the /users/{username} endpoint is per installation, but I'm not sure
-        # how to tell which installation token to use, unless there is a way to build a huge map of
-        # username -> token, or we just try each one in order
-        def _get_avatar_by_username(self: Any, username: Any) -> Any:
-            return f"https://github.com/{username}.png"
-
-        import types
-
-        avatar._get_avatar_by_username = types.MethodType(  # noqa: SLF001
-            _get_avatar_by_username,
-            avatar,
-        )
-
-        return avatar
+        return AvatarGitHub()
 
     def create_auth(self) -> AuthBase:
         assert self.config.oauth_id is not None, "GitHub OAuth ID is required"