cts: Disable ZSL to verify preview/still timestamp

When ZSL is enabled, still and preview timestamps may be out of order.
Disable ZSL in order to verify preview and still timestamps.

Test: FastBasicsTest#testCamera2
Bug: 78468960
Change-Id: Iab2386cb1c11eafacfe973c114bc8bc3c604fd61
1 file changed