WYSIWYG unable to set default value in ui component

[omiroshnichenko]

Description

Fix default value for wysiwyg component.

Fixed Issues

1. WYSIWYG unable to set default value in ui component #10048: WYSIWYG unable to set default value in ui component

Manual testing scenarios

1. Add default value for content field in cms_page_form.xml

...
<field name="content" formElement="wysiwyg">
    <argument name="data" xsi:type="array">
        <item name="config" xsi:type="array">
            <item name="source" xsi:type="string">page</item>
            <item name="default" xsi:type="string">blabla</item> <!-- Add this item -->
        </item>
    </argument>
    <settings>
        <additionalClasses>
            <class name="admin__field-wide">true</class>
        </additionalClasses>
        <label/>
        <dataScope>content</dataScope>
    </settings>
    <formElements>
        <wysiwyg>
            <settings>
                <wysiwyg>true</wysiwyg>
            </settings>
        </wysiwyg>
    </formElements>
</field>
...

2. Open Cms Page creation form
3. Verify that default value present in wysiwyg

Contribution 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)
• All automated tests passed successfully (all builds on Travis CI are green)

[magento-engcom-team]

Hi @VladimirZaets, thank you for the review.
ENGCOM-3381 has been created to process this Pull Request

[magento-engcom-team]

Hi @omiroshnichenko. Thank you for your contribution.
We will aim to release these changes as part of 2.3.1.
Please check the release notes for final confirmation.