minadbd: Support `adb rescue getprop`.

It dumps all the allowed properties, similar to `adb shell getprop`.

Bug: 134027350
Test: Run the command under rescue mode.
Change-Id: Ic0864ca0fb51505ec1e4f38af2464591aa576201
Merged-In: Ic0864ca0fb51505ec1e4f38af2464591aa576201
(cherry picked from commit d8db81a0)