Allow for static flag reads in the BQ helper.

This fixes a build issue when using flags in the stagefright bq helper.

Bug: 393639172
Flag: com.android.graphics.libgui.flags.wb_media_migration
Test: builds, run presubmit tests.
Change-Id: Iccf51f56ecb1c1c1d96f5b7992093bb9c01dbf58