[BUGFIX] Fix path issue in gruntfile.js

This patch fix a wrong path for module icon in Gruntfile.js

Resolves: #84510
Related: #84159
Releases: master
Change-Id: I89686bf3eb7611df0c0cffb16c2f660c56dfd941
Reviewed-on: https://review.typo3.org/56402


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Tobi Kretschmann <tobi@tobishome.de>
Reviewed-by: Mathias Schreiber <mathias.schreiber@typo3.com>
Tested-by: Mathias Schreiber <mathias.schreiber@typo3.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>