Bug description

Hey,

A lot of our forms have multiple submit buttons which submit the form to different endpoints for different actions.

However, this then breaks the [up-validate] behaviour because the validation submissions aren't sent to the action on the form, but rather one of the [formaction] attributes from the other submit buttons. I've never used Glitch before so haven't implemented any server logic, but there's a very minimal repro here:

https://vigorous-local-akubra.glitch.me/

If you focus the input, then tab out of it and check the browser network tab you can see that it submits to the wrong URL.

Expected behavior

[up-validate] should be submitted to the default action of the form.

Browser version

• OS: Windows 10
• Browser: Chrome
• Version 110.0.5481.177

Additional context

Unpoly v2.7.2