[Translations] Translation of elements' help text breaks if the Element text format setting is not empty

Problem

When the html_editor.element_format configuration is set to the key of a text format (instead of being left blank) the texts for webform elements become untranslatable in the UI since the rich text editor is no longer displayed.

The description and more texts—that are very similar—still show in the translation form as expected.

Steps to reproduce

• Install Webform v6.2.x-dev (tested at f6b7ff79f81357a5566aacaa4200c3f92fd795b0)
• Enable webform and webform_ui
• In /admin/structure/webform/config/elements set Element text format to Full HTML
• Enable content, configuration and interface translation
• Enable at least one additional language
• Create a webform with a single element (tested with a checkbox)
• Add a translation for the webform through the UI

Expected outcome: the help text can be translated in a similar way to description and more.
Actual outcome: the help text is displayed as plain text in the source column and the textarea is missing.