Update git submodules

* Update helpcontent2 from branch 'master'
  - Use window.location.href = ...; instead of window.open(..., '_self');
    
    Otherwise the interim URLs end up in the history.
    
    Change-Id: If99aa1a29126f93387d2f5a6460cc0d43b488cd9
    Reviewed-on: https://gerrit.libreoffice.org/58867
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 7ab3eded

-Subproject commit 5c1d1eb33951982ffa5352980d4713489c0d98ae
+Subproject commit 7ab3eded419b6fddbdd9d7a7c1f676b3720950c0