Add tooltips to Tab Bar

[jwold]

Feature description

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There are times when the tab bar headings can be set without labels. In this scenario an icon is added without a label. We should ensure that the icon can be given a tooltip.

Acceptance criteria

1. Handle this however we handle the Icon Button block.

• Add a new label input field into the block sidebar.
• Allow the new field to be visible regardless of whether there is a heading on the tab or not.

Note: Similar to #224 where we could add a field in the block sidebar settings to add a tooltip.

Implementation brief

QA testing instructions

Demo

Changelog entry

[jwold]

We recognize that this is not necessarily ideal because you could have a tooltip that is the same as the label. But for now this seems like an ok solution to ship with.

cc @jbingham and @yasmineevjen

[jwold]

Closing for now, goes against guidance.

[jauyong]

Handle this however we handle the Icon Button block.

[jauyong]

@jwold I've added a Tab block with no label but I don't see an icon being added. Can you confirm the issue?
https://dev-mdc-web.pantheonsite.io/wp-admin/post.php?post=1909&action=edit

Editor:

Front end:

[jwold]

@jauyong I think the issue is ready for engineering, but recorded a quick video to make sure.

Video: https://v.usetapes.com/fvY0cE215T