Delete outdated patch code

Author: dlqqq

jupyter_server/auth/login.py

@@ -44,14 +44,6 @@ def _redirect_safe(self, url, default=None):
         # instead of %5C, causing `\\` to behave as `//`
         url = url.replace("\\", "%5C")
 
-        # Prevent open redirect attacks by blocking URLs that start with //
-        # These are protocol-relative URLs that can redirect to external sites
-        if url.startswith("//"):
-            self.log.warning("Not allowing login redirect to protocol-relative URL %r" % url)
-            url = default
-            self.redirect(url)
-            return
-
         # urllib and browsers interpret extra '/' in the scheme separator (`scheme:///host/path`)
         # differently.
         # urllib gives scheme=scheme, netloc='', path='/host/path', while