Enable wysiwyg toggle button in pagebuilder text form

[smartexcan]

Enable the toggle button for the wysiwyg editor in the pagebuilder text form modal.
Editor could not be accessed if set to disabled by default in config. (see linked issue)

Fixed Issues

fixes #904

Manual testing scenarios (*)

1. Set Stores > Configuration > General > Content Management > WYSIWYG Options > Enable WYSIWYG Editor to "Disabled by Default"
2. Open page with page builder field.
3. Add text content-type to stage
4. Open edit form for text content-type, check toggle button visible

Checklist

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• README.md files for modified modules are updated and included in the pull request if any README.md predefined sections require an update
• All automated tests passed successfully (all builds are green)

[smartexcan]

@magento run all tests