Enhancement: Export individual contact form without filtering first

### Impacted plugin

Jetpack

### What

Export individual contact form without filtering first

### How

1. Visit `wp-admin/edit.php?post_type=feedback`
2. Select a source from the dropdown
3. Click `Export`
4. Click `Download`

I expected the results to only include submissions for the selected post, but they actually contain submissions for all posts. It looks like you first have to click `Filter`, wait for the refresh, and then click `Export`.

That feels unintuitive, and it introduces an unnecessary delay while I wait for the page to be refreshed in order to _display_ the filtered posts, before they're fetched again in order to _export_ them.

These two actions should be independent of each other IMO. In many use cases, I don't want/need to display before exporting.

Start at wp-admin/edit.php?post_type=feedback and trace the source dropdown through Filter, Export, and Download. Verify that exporting immediately after selecting a source produces only that post’s submissions, without requiring the page refresh.

Written by the indexing model from the issue text.