Disallow fastboot to modify locked DSU

This enhances the security requirement by only allowing
the owner app to change a locked DSU.

(Cherry-picked from aosp/2744993)

Bug: 277691885
Bug: 296985785
Test: 1. ensure device is OEM locked
      2. adb shell am start-activity \
         -n com.android.dynsystem/com.android.dynsystem.VerificationActivity \
         -a android.os.image.action.START_INSTALL \
         --el KEY_USERDATA_SIZE 2147483648 \
	 --es KEY_DSU_SLOT foo.lock
      3. adb reboot fastboot
      4. `fastboot gsi disable|wipe` should be blocked

Merged-In: I1a0cb8a074412468d16043ddf4101fbb76490115
Change-Id: I1a0cb8a074412468d16043ddf4101fbb76490115