Agent Beta - Add some front-end validation to the create new agent modal

[melohagan]

Checklist

• I have searched budibase discussions and github issues to check if my issue already exists

Hosting

• Cloud

Describe the bug
The Confirm is visible when no agent name has been supplied. If you click the button, it spins indefinitely and throws an error.

To Reproduce
Steps to reproduce the behavior:

1. Create new agent
2. Without typing in a name, click Confirm
3. See the hanging spinner
4. The console log shows the error.

Expected behavior
Validation should be added to the create new agent modal so that you cannot get into a broken state.

Screenshots

Additional context
It would also be nice if hitting the enter key confirmed the modal. (ESC already closes the modal, so makes sense to also be able to submit with the keyboard)

[melohagan]

Additionally I noticed that apps, automations and agents do not enforce a unique name constraint. This should be added.