Resolves: https://musescore.org/en/node/301259
See also https://github.com/musescore/MuseScore/pull/5728/
The problem occurs in several different overrides to
getPropertyStyle() for various different text classes.
The function is supposed to determine
which Sid to use for Pid::OFFSET, based on placement above/below.
But that calculation should only be relevant
if the element is using the default text style for its type.
Otherwise it should use the offset in the current text style.
This code removes the overrides for getPropertyStyle() in each class,
instead modifying TextBase::getPropertyStyle() to check
if the element is using its default text style or not,
and then only if so does it use the placement to select a Sid.
Otherwise it uses the offset of the current text style.
