Update git submodules

• Update extensions/Math from branch 'REL1_43' to 883be554dbca6a681f12fd44d2efdda153844d39
  • Fix: rendering of _1
    
    _1 was converted by the preprocessor to \displaystyle _1 and the DQ node got \displaystyle rather than an empty node as input.
    
    This change renders the base (here displaystyle) and checks if the result is empty instead of checking if the input is empty. Thus, both variants {}_1 and _1 render correctly
    
    Bug: T386071 Change-Id: I0366a8d6636368d437c9905961989e9882d4e1f6 (cherry picked from commit b4f3514c2a27c948074cf2f61b88e85c58cf9dd6)