Press This: Upgrade bookmarklet notice appearing on directly accessed URL

[kraftbj]

In 4.2, one feature of Press This is the ability to directly access wp-admin/press-this.php and scanning a URL instead of only relying on the bookmarklet.

In [32106], bookmarklet version checking was moved to PHP to display if either the version is not indicated or under the current version (8).

Since the directly accessed URL will never have the version of the bookmarklet included, it is always displaying the notice.

Since the version number has been included in the bookmarklet since [7927], which had the bookmarklet pointing to /wp-admin/quick-post.php before it was branded as Press This, thus all released versions of WP has included the version number, it is probably safe to not display a notice if no version is present.

[kraftbj]

Changes empty check for isset so the notice does not display with no version is indicated.

[helen]

Since we now include a direct link in Tools, moving into 4.2.

[azaozz]

In 32122:

Press This: do not show the bookmarklet upgrade notice when accessing directly press-this.php.
Props kraftbj. Fixes #31968.