Block Editor: Don't show back compat or incompatible meta boxes in Options.

Meta boxes that exist for back compat, or that are incompatible with the block editor aren't displayed, so they don't need an option to display or hide them in the Options dialog.

Merges [43856] from the 5.0 branch to trunk.

Props noisysocks.
Fixes #45249.

Built from https://develop.svn.wordpress.org/trunk@44222


git-svn-id: https://core.svn.wordpress.org/trunk@44052 1a063a9b-81f0-0310-95a4-ce76da25c4cd