Update git submodules

* Update helpcontent2 from branch 'master'
  - tdf#121065 Replace Attributes, Brackets and Format Icons with SVGs
    
    Replace Attributes, Brackets and Format Symbols PNG images with SVG
    and updated 03090800.xhp, 03090200.xhp and
    removed at21706 in Package_html_media.mk
    also removed lines with at21717, at21718, at21719, at21720
    and removed line with im21106.png in Package_html_media.mk
    
    Change-Id: If504f6a39845695aef30a61826fecf8433a326ed
    Reviewed-on: https://gerrit.libreoffice.org/66659
    Tested-by: Jenkins
Reviewed-by: Olivier Hallot <olivier.hallot@libreoffice.org>
    

helpcontent2 @ 97643084

-Subproject commit a02a91b543cd098a81da3f82ff22e3d83f732aa5
+Subproject commit 97643084f932f8e6c9a3f13d4961b00b333a8573