"Installed Plugins" should link to the all plugins screen

[nacin]

Some time back, we converted the menu label to "Installed Plugins."

However, we still keep a user preference for which plugins screen they visited last, and then always take them to that screen next.

It's a nice preference, sure, but it can be confusing, and I doubt people realizing their preferences are being saved for their return. It probably just makes them do another click or two.

Now that we've renamed the menu, the behavior is inaccurate and poor UX.

We should remove the behavior.

This came up in usability testing at WC Portsand the other week, I actually thought it was a new bug. The preference is too subtle for people to get it, because they visit those screens so infrequently. Please change so links go directly to appropriate screens as originally intended in the design.

In [18811]:

Stop remembering the last viewed plugins screen. Always show all plugins when returning to plugins.php. fixes #18810.

In [20022]:

Do not save the last visited tab on the multisite Network Themes page and Site Themes tab. These are poor UX, see #18810 for plugins. Entering these screens will always default to 'all' themes view. see #20103.

Test (see #18767)