Regression with mobile formatting toolbar

[jasmussen]

Some time in the most recent releases, the mobile block-toolbar regressed. The intended behavior is that it works the same as "Fix toolbar to top", but always enabled on mobile. Here's the behavior of master:

As such, the bug is that we need to enable, no matter any previous setting, fix toolbar to top on mobile always.

This would also fix a secondary issue, as you can see, where the iPhone selection popup toolbar covers the block toolbar.

Another issue is that we should probably never enable isEditing mode on mobile, the primary reason being that if we do, it's hard to get back the movers, trash and ellipsis, because it's not enough to just tap on the text to get the block UI to show, you have to select a different block first.

[jasmussen]

This is fixed in 2.9 as of #6347