Allow data-dialog-options to be set as array.

Problem/Motivation

Currently to pass jQuery dialog options onto drupal's dialogs you have to do something like:
'data-dialog-options' => Json::encode(['width' => 400]),
This is kinda of annoying

Proposed resolution

Automatically encode the options if they are an array.

Remaining tasks

Patch
Test

User interface changes

None

API changes

data-dialog-options could be set as a json encode string or an array.

Data model changes

None