l2cap: Fix using FCS field in S/I frames

As per Version 6.0 | Vol 3, Part A, 5.5 Frame Check Sequence (FCS) option

If both sides configure channel for `No FCS`, then this field shall be
skipped.

Android by default uses FCS and this fix is needed only for PTS tests
and in case other products would like to configure stack in a different
way.

Bug: 371948052
Bug: 372605959
Test: mmm packages/modules/Bluetooth
Test: manual PTS tests L2CAP/FOC/BV-05-C
Flag: com.android.bluetooth.flags.l2cap_fcs_option_fix
Change-Id: I62eeeb0e497be1819d8f83bf25997641392c022a