Dropdown does not anchor to bottom after filtering

Summary

The dropdown for the new issue page are not anchored to the bottom after filtering

Steps to reproduce

1. Go to a repo that has issue labels setup
2. Create an issue in that repo
3. Open the labels dropdown
4. Type to filter the labels dropdown

Expected behavior

Dropdown is anchored to the bottom

Actual behavior

Dropdown is anchored to the top

Relevant logs and/or screenshots