Description

The inverted block toolbar/drag handle in select mode is offset slightly compared to the block toolbar:

This PR fixes that:

Note that now that IE11 support is no longer necessary, there is a huge opportunity to refactor the block toolbar to leverage flex and remove all the gnarly margin rules on content inside, replace them entirely with gap and drastically simplifying things. But it's a larger undertaking, and this is a small fix in the mean time.

How has this been tested?

Insert a block, select it, then press Escape. Observe the block icon and drag handle ideally overlapping precisely in both states.

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• I've tested my changes with keyboard and screen readers.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR (please manually search all *.native.js files for terms that need renaming or removal).