MediaThumbnailFormatter produces unhelpful text alternative and title attributes for media thumbnails

Problem/Motivation

We have trouble with alt text for Thumbnail formatter. It is very similar to Media entity bug → , but we use module Media in core.

The thumbnail alt test for media items is often unhelpful and is Thumbnail. In this instance the accessibility maintainers have decided that no alt text for thumbnails is preferable. Also they pointed out that the title attribute is problematic and should not be used at all - see #27and #4.

Proposed resolution

• Remove the title attribute for thumbnails
• Remove alt for thumbnails unless we have sensible text which we do for images.

Remaining tasks

User interface changes

Thumbnail don't have title attributes. Alt text on image media thumbnails is helpful. Alt text on other media types is omitted.

API changes

None

Data model changes

None

Release notes snippet

N/a