[TASK] Paste clipboard content icon: fa-clipboard

Change paste clipboard content icon:
use fa-clipboard not fa-caret-down

Resolves: #63264
Releases: master
Change-Id: Idd092c6d79290e0287deabc4dff4f2f87381367e
Reviewed-on: http://review.typo3.org/35012
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>