Hide bulk actions dropdown when there are no posts

[swissspidy]

This is a followup on #21856 and #21015.

The bulk actions dropdown is useless if there aren't any posts in the current view. We should hide it, just like the other dropdowns mentioned in the above tickets.

[mehulkaklotar]

check for if items or posts are there then display added

[wonderboymusic]

In 34076:

List Tables: don't render "extra tablenav" if there are no posts. This includes Bulk Actions, Dates Dropdown, Category Dropdowns, Pagination.

Also ensure that the Months dropdown, when it is shown, shows months from the proper set of posts.

Props egower, CoenJacobs, MikeHansenMe, mehulkaklotar.
Fixes #33824, #21015, #21856.

[ocean90]

[34076] includes an UX issue for comments and maybe other screens with extra filters

1. Go to wp-admin/edit-comments.php
2. Make sure you have no trackbacks in your list
3. Filter by pings
4. You will get the "No comments found." view without any filters
5. Now click on the "All" link (wp-admin/edit-comments.php?comment_type=pings&comment_status=all)
6. Because it includes the filter you are at step 4 again

[wonderboymusic]

On it

[wonderboymusic]

In 34707:

List Tables: only hide bulk actions when there are no items, don't hide all of the extra table nav.

Fixes #33824.

[kitchin]

For future reference, see also https://core.trac.wordpress.org/attachment/ticket/29789/29789.fix2.diff in #29789. We could disable the bulk drop-down selects in js instead of html. I don't know how we handle it when the table loads dynamically, but in that case the solution is js anyway, so might as well make it easy.