Update git submodules

* Update helpcontent2 from branch 'master'
  - Revert "Create XSLT replacement table for missing icons"
    
    This reverts commit 61f44912beec99f6211399ce567274aa369f817d.
    
    Change-Id: Icd69ccd4f487a82426a00169728ec62bbff6d0b6
    Reviewed-on: https://gerrit.libreoffice.org/70350
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 2d21ebb7

-Subproject commit 12aff9b55df5cfc0282ec9ee7d359fb843291a79
+Subproject commit 2d21ebb74b31546cf7dd133df9f8c4951d325c80