Too large margin for bridge will cause overflow for
shell model. But too small margin for top/bottom will
cause infill area discontinuous.
Using different margin for top/bottom and bridge to
make a balance.
Signed-off-by: salt.wei <salt.wei@bambulab.com>
Change-Id: I9ba8388b85b978ae39caf2df04f96c704b5d2e05