[BUGFIX] Use type "button" for accessible paste content buttons

The paste content buttons now have the type "button" set
to not falsely behave as submit buttons, which is the default
if no type is defined.

See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/button#attr-type

Note: In this case the regular submit event is prevented by
JavaScript which leads to no actual functional change here.

Resolves: #92668
Relates: #92653
Releases: master, 10.4
Change-Id: I22f80778eab02b9c9ada9177ae5f72cfca2f55ff
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/66248


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Daniel Haupt <mail@danielhaupt.de>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Daniel Haupt <mail@danielhaupt.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>