Gate permissions hub assistant handling behind flag

Update the user sensitive flags of the current assistant whenever it is
added or removed from the role, only when the device config flag is set.
Adds camera/mic icon flags, and only shows location on
reviewOngoingUsageFragment when permission hub is enabled.

Fixes: 159998363
Test: manual
Change-Id: Ice52dc044c34b31e6930f461008fbeafa70b1e3b