Revert "ImageDecoder: add "image/avif" to support list"

Revert submission 22114263-cherrypick-avif_cts-6vuisjq0md

Reason for revert: b/275081444

Reverted changes: /q/submissionid:22114263-cherrypick-avif_cts-6vuisjq0md

Change-Id: I2cfedc608ae8803f811ae1d99b2f4e057ae3db81
1 file changed