Adding flag com.android.server.display.feature.flags.virtual_display_limit to trunk_staging.

This change was automatically created by advancing the Gantry workflow at:
https://releasetracker.partner.android.com/changes/70khuji000001?build_unique_id=android_platform_display_manager
Do not edit this file manually or revert this change - use the Gantry workflow to manage the state of this flag.

Bug: 261791612
Change-Id: Icd5856863cc327e521432cab0417b2327115a7c3
Flag: com.android.server.display.feature.flags.virtual_display_limit
Ignore-AOSP-First: AConfig change for future AOSP release