floss: Don't run VSC commands in l2cu_set_acl_priority

These VSC are not available on ChromeOS boards and causes crashes.

Bug: 322734793
Tag: #floss
Test: mmm packages/modules/Bluetooth
Test: bluetooth_AdapterAUHealth.au_a2dp_test.floss
Flag: EXEMPT floss only changes
Change-Id: I9bf2307c1052ff07db45e52bc063cd079cc3c1f9