Fix thumbnail hvcc key in ItemTable

In HEIF files the hvcc for main image and the thumbnail
are separate. Add AMEDIAFORMAT_KEY_THUMBNAIL_CSD_HEVC for
thumbnail hvcc, and set it in ItemTable.

test:
- thumbnail test from the bug;
- manual testing of HEIF image decoding of various files;
- cts MediaMetadataRetriverTest.

bug: 128494513
Change-Id: I219a86cf362f641d546236dda78e8559ffcfa8aa