cleanup: Remove more unused imports.
MODIFY
zulip_bots/zulip_bots/bots/file_uploader/test_file_uploader.py
zulip_bots/zulip_bots/bots/file_uploader/test_file_uploader.py
from unittest.mock import Mock, patch
from zulip_bots.test_lib import (
- get_bot_message_handler,
- StubBotHandler,
BotTestCase,
DefaultTests,
)

MODIFY
zulip_bots/zulip_bots/bots/followup/test_followup.py
zulip_bots/zulip_bots/bots/followup/test_followup.py
from zulip_bots.test_lib import (
- StubBotHandler,
BotTestCase,
DefaultTests,
- get_bot_message_handler,
)

cleanup: Remove more unused imports.

Signed-off-by: Anders Kaseorg <anders@zulipchat.com>