Update vnc_server communication.

It is actually using a socket to talk to the sensors hal,
not system_server where the sensors hal was formally hosted.
If the sensors hal is moved back to system_server, this new
rule will still be applied properly.

Bug: 71707530
Test: boot device, check for denials, but note that /var/run
  is currently not being mounted on the device.
Test: one less neverallow hit when PRODUCT_SEPOLICY_SPLIT is enabled

Change-Id: I4f2e7c31a00ce659cd2ce0a79ff96f33a4eb9516
(cherry picked from commit 37556a8eeec29dc4e873d282de7bba94d4a536bf)
(cherry picked from commit 153195b45b827fc39c23e43f55e0cac328e8315a)