[BUG] av1 main10 profile fails Intel DG2 ANV driver

## Describe the bug

The encode test encode_av1_main_profile_10bit fails to encode with error:

encode_av1_main_profile_10bit

vk-video-enc-test: ../src/intel/isl/isl_format.c:701: format_info_exists: Assertion `format != ISL_FORMAT_UNSUPPORTED' failed.

## Setup

- OS: Linux
- GPU: A750 Graphics (DG2) (8086:56a1)
- Driver Version: Mesa 26.3.0-devel (git-e9a87f80b2)
- Sample Application: Encoder
- Sample Application Version: 0.5.0-devel

## Expected Behavior

Unsupported message or supporting the main10 profile

## Observed Behavior

## Steps to Reproduce

## Screenshots

## Related non-duplicate issues

## Additional Information

Start by reproducing encode_av1_main_profile_10bit with vk-video-enc-test on the Intel A750/DG2 setup. Inspect the failure reported at src/intel/isl/isl_format.c:701 and compare the driver’s handling of the AV1 main10 profile. Done means the sample reports unsupported cleanly or encodes successfully with main10 support.

Written by the indexing model from the issue text.