Fixes#20998
The basic modal actions were set up for basic confirmation-style modals,
however this modal also has a special form input, which instead requires
a form in the modal itself.
The basic modal actions are indirectly controlled by JS and are simple
`<div>` elements, whereas this requires a `<button>` to submit.
This appears to be similar to how we do it in (for example) the repo
deletion modal.
Signed-off-by: jolheiser <john.olheiser@gmail.com>
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