🚑 [#4362] Prevent crash due to translatable defaultValue

Textfield and textarea have the multiple: true option, which turns the defaultValue
into an array of strings rather than a single string, and that
doesn't play well with the translations machinery or missing
translation detection.

Open Forms 2.7.0 removes support for translations for this
property, and older versions get a hotfix to prevent the
crash from happening during detection.

Backport-of: #4387

src/openforms/js/components/formio_builder/translation.js

@@ -37,8 +37,6 @@ const ALWAYS_TRANSLATABLE_PROPERTIES = ['label', 'description', 'placeholder', '
  *   test the property path against.
  */
 const ADDITIONAL_PROPERTIES_BY_COMPONENT_TYPE = {
-  textfield: ['defaultValue'],
-  textarea: ['defaultValue'],
   content: ['html'],
   fieldset: ['legend'],
   editgrid: ['groupLabel'],