adb: checks device state when using adb disable-verity for AVB

adb disable-verity will toggle a flag in /vbmeta and introduce AVB
verification error on next boot. If the device is LOCKED, it will make
the device unbootable because verification error isn't allowed when the
device is locked.

Also indicating 'adb root' when failed to get verity state.

Bug: 70969453
Test: adb disable-verity should pop-up warning if the device is locked.

Change-Id: I1ed705e34334ea2231c96b16ddb8d225067af2f0