Multi select gutenberg fix

[jomurgel]

May address #679, but I was unable to replicate the issue in that task, so I'm unclear.

• Resolves render issue with the chosen select field on Gutenberg-enabled posts. Select fields, in Gutenberg posts, are returning .is(":visible") or :visible generally, as false on load. Whereas it returns true for non-Gutenberg posts. Unclear why that would be, but removing the :visible qualifier resolves initializing Chosen.js on the sidebar.
• Removes the width of 350px and replaces with max_width: '100%' which works both in Gutenberg and non-Gutenberg posts to prevent the select dropdown from expanding past its bounds. Chosen already sets the width inline, this prevents miscalculation overages.

[gfargo]

Hey @jomurgel,

Looks like this issue also extends to single autocomplete fields as well.

By removing :visible from fieldmanager-automcomplete.js here resolves the issue there as well.

Edit:

Just seeing #710 was created to handle single autocomplete fields in Gutenberg. #717 was created to address this issue. Think we can keep this PR limited to addressing the issues with the Chosen library.

[pattiereaves]

🦄

[jomurgel]

PR #729 might be a better solution for resolving the issues with the autocomplete field/sortable field behavior on load. A replacement for that part of this PR vs removing the :visible selector check right off.

There was quite a bit of discussion about the implications around removing that check altogether, though in my testing, that did not seem to have any real-world effects on rendering/initting fields in Gutenberg or 4.9- WP installs with fields shown or hidden.

[kevinfodness]

Fixed via #757