JAWS: Insert Image (via URL) toolbar dropdown button is not labelled

[Mgsy]

📝 Provide detailed reproduction steps (if any)

1. Go to https://ckeditor.com/docs/ckeditor5/latest/features/images/image-upload/images-inserting.html.
2. Start JAWS, use CTRL+Insert+C to get the available list of dropdowns.

✔️ Expected result

The image toolbar dropdown is labelled properly.

❌ Actual result

The image toolbar dropdown is labelled as "Unlabeled 1".

---

If you'd like to see this fixed sooner, add a 👍 reaction to this post.

[mlewand]

I checked this issue and it's not that the button as a whole doesn't have a label but only the down arrow part of split button doesn't have a label (I mean it has aria-labelledby but it points to an empty element).

We have two options here:

1. We can stay with generic "insert image" label (just like it is for the main button).
2. We can customize label for the dropdown arrow to "Insert image via URL".

I find the latter to be more appropriate here as it better describes the component that will be shown. So let's implement customized label. Good thing is that we'll have the localization ready for it (as it reuses the label from the dropdown).

This issue is closely related to #11833 and should be done after #11833 is merged.

[jswiderski]

This issue has also been reported by one of our clients:

• aria-labelledby attribute references element that is empty
• Element's default semantics were not overridden with role="none" or role="presentation"
• Element has no title attribute (this can probably be omitted when aria-labelledby is not empty)

[oleq]

• The important part of this issue was addressed in Added missing tooltip for split button's down arrow #11859. 
• Insert Image (via URL) toolbar dropdown tooltip updated #11946 brought some extra tests.