Update git submodules

* Update helpcontent2 from branch 'master'
  - Update New Features video for 6.2 help online
    
    Change-Id: Ibe32ecee310b5d844c18e3cebec534328219325f
    Reviewed-on: https://gerrit.libreoffice.org/66695
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 911e8ecc

-Subproject commit 97643084f932f8e6c9a3f13d4961b00b333a8573
+Subproject commit 911e8ecc3837b3ab6a344c3951119a70233d6d9e