Selectables visual fixes

[sebastian]

The most important fix here is the bug fix for safari where the selectables header would get oddly compressed when the list of columns was long. Additionally this pull-request fixes:

• all browsers: padding at the bottom of the selectables list making the scrollable selectables list fall short of the full height of the screen
• all browsers: change alignment of status pill from baseline to middle. This is a change from not quite right, to not quite right unfortunately, but at least it seems like a change from not quite right to slightly less wrong.

Pill alignment before:

Pill alignment after:

[aircloak-robot]

Standard tests have passed ❤️

[gampleman]

IMO baseline alignment looks much better.

[aircloak-robot]

Pull request can be merged 😊

[sebastian]

IMO baseline alignment looks much better.

Baseline alignment is way below the text?!