Add regression test for image upload in TextArea properties

We should add an integration test that tests uploading images in text area properties and verifies that they are saved in:

1. Editable properties - regression reported as XWIKI-24513
2. The object editor - not reported but also affected by the same regression
3. Comments - regression reported as XWIKI-24546
4. Annotations - original scenario reported in XWIKI-24546