camera/device/3.2: Add custom vendor operating modes

This fixes a perf/feature regression from the legacy HAL definitions;
previously, vendor implementations could use custom values with this
field to implement custom features on their devices.

Add several enum values that can be used for this purpose.

Test: New CTS test passes
Bug: 34853980
Change-Id: I1b37a9511326178b8eb7536ff99e14d83be3b0c2