Fix duplicate project board when hitting `enter` key (#27746)

Fix duplicate project board when hitting `enter` key (#27746)

When hitting the `enter` key to create a new project column, the request
is sent twice because the `submit` event and `key up` event are both
triggered.
Probably a better solution is to rewrite these parts of the code to
avoid using native jQuery but reuse the `form-fetch-action` class. But
it's beyond my ability.