This addresses the following denials:

avc: denied { fowner } for comm="rm" scontext=u:r:vold_prepare_subdirs:s0 tcontext=u:r:vold_prepare_subdirs:s0 tclass=capability
avc: denied { getattr } for comm="rm" scontext=u:r:vold_prepare_subdirs:s0 tcontext=u:object_r:storaged_data_file:s0 tclass=file
avc: denied { relabelfrom } for comm="vold_prepare_su" name="storaged" scontext=u:r:vold_prepare_subdirs:s0 tcontext=u:object_r:system_data_file:s0 tclass=dir
avc: denied { getattr } for comm="rm" scontext=u:r:vold_prepare_subdirs:s0 tcontext=u:object_r:system_data_file:s0 tclass=file

Bug: 77875245
Test: Boot device.
Change-Id: Id67bc99f151a6ccb9619bbfb7080452956405121
Test: Mislabel directories used by vold_prepare_subdirs, reboot, and
ensure it can relabel them without denials.
Test: Add user, reboot, delete user, reboot, observe no denials.