Export libacryl related flags to soong

Export BOARD_LIBACRYL_DEFAULT_COMPOSITOR, BOARD_LIBACRYL_DEFAULT_SCALER,
BOARD_LIBACRYL_DEFAULT_BLTER, and BOARD_LIBACRYL_G2D_HDR_PLUGIN to
soong. Also export one include path to sooong but check if the path
exist before export to soong due to soong does not allowed non-existed
path.

Bug: 370414334
Test: m libacryl
Change-Id: Ib7f7af43da0359e691dee8bd538664147704c648