management: Remove rename_stream.

Now that it is trivial to rename a stream in the UI, And due
to the fact that the command has been broken for 3 years unnoticed,
it is unnecessary to maintain it anymore.

Fixes #22244.

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

zerver/management/commands/rename_stream.py

@@ -1,26 +0,0 @@
-from argparse import ArgumentParser
-from typing import Any
-
-from zerver.actions.streams import do_rename_stream
-from zerver.lib.management import ZulipBaseCommand
-from zerver.models import get_stream
-
-
-class Command(ZulipBaseCommand):
-    help = """Change the stream name for a realm."""
-
-    def add_arguments(self, parser: ArgumentParser) -> None:
-        parser.add_argument("old_name", metavar="<old name>", help="name of stream to be renamed")
-        parser.add_argument(
-            "new_name", metavar="<new name>", help="new name to rename the stream to"
-        )
-        self.add_realm_args(parser, required=True)
-
-    def handle(self, *args: Any, **options: str) -> None:
-        realm = self.get_realm(options)
-        assert realm is not None  # Should be ensured by parser
-        old_name = options["old_name"]
-        new_name = options["new_name"]
-
-        stream = get_stream(old_name, realm)
-        do_rename_stream(stream, new_name, self.user_profile)