va: encoders: fixes for dynamic reconfiguration
va{vp9,av1}enc: reconfigure when properties change
examples: vaenc-dynamic: support target percentage change in QVBR
examples: vaenc-dynamic: ignore bitrate change with ICQ too
va: encoders: don't assert at target percentage when QVBR
Instead of asserting, just get the max value between the current value and 10,
which is the minimum required by QVBR.
examples: vaenc-dynamic: add vp9, av1 and low power tests
cc: @He_Junyan