Semantic elements for non-link links: Quick Edit and Bulk Edit

[afercia]

In the Quick Edit form:

• the "Cancel" and "Update" button are currently links that look like buttons

In the Bulk Edit form:

• same but just for the "Cancel" button

For semantics and accessibility, they all should be buttons. See related #26504.

[afercia]

In the proposed patch:

• Quick Edit and Bulk Edit: make the Cancel and Update buttons real buttons

To quickly check without the need to install a screen reader, you can apply the patch and test the buttons can now be activated pressing Spacebar on your keyboard.

[afercia]

Thinking a screenshot would be useful to make clear why buttons should be buttons :) We don't want them to be reported as "Internal link" (or "link" depending on the screen reader used). See below the ChromeVox console:

[wonderboymusic]

In 32869:

Use <button> instead of <a> for non-link links in Quick Edit.

Props afercia.
Fixes #32213.