Update git submodules

• Update extensions/MobileFrontend from branch 'wmf/1.31.0-wmf.17'
  • Fix regressions with updated lead intro transform
    
    This is a combination of 2 commits:
    1. Avoid notice in lead paragraph transform when encounter infobox like elements
       
       XPath query can return tables that look like infoboxes as contains(@class,"infobox") is not the same as hasClass('infobox'). Thus getInfoboxContainer can resolve to false. This test and fix guards against that.
       
       Bug: T185106 Change-Id: I5a8fbbb956365de9af09ee8d238fb3389e8f2cef
    2. Remove blacklisted content before applying transforms
       
       Previously we removed all blacklisted elements AFTER applying transforms such as moving lead paragraph.
       
       This is unnecessary and can lead to problems, for example infoboxes inside elements which are to be removed, might be moved above the lead paragraph and skip the blacklisting altogether. This also leads to unnecessary logging when the move is not possible.
       
       HtmlFormatter::filterContent takes care of content removal so lets do that BEFORE our transformations explicitly.
       
       Bug: T185040 Change-Id: I18bc97fa37bdc53e61cb6de79fb6bc1158ffd9fe