Move the view mode switcher into screen options for multisite users and sites

[afercia]

In the Posts screen, WordPress used to have two links to "switch mode" from the normal list view to the "excerpt" view. In WordPress 4.4 these links were moved to the Screen Options panel, see [35357].

However, on multisite the "Sites" and "Users" screens still show the switch mode links at the top right of the main table. For consistency, and for the design / UI reasons explained in #22222, they should be moved to the Screen Options as well.

[afercia]

For history: this is how the "switch links" used to look like in WordPress pre-4.4:

[johnjamesjacoby]

I never liked that these links moved to screen options for Posts. I’d rather revert that than move these.

If the issue is that the modes are not useful, we should remove them, or make them more useful.

Plugins do use these mode switchers for more obvious things (calendars with month/week/day modes, etc…)

[afercia]

I'd agree there should be some consistency, the multisite admin is not a separate realm and users shouldn't be forced to learn new UI patterns depending on where they are.
On the other hand, I'm not sure to fully understand what an "Excerpt View" is about, when it comes to Sites and Users :)