Remove -language-version flags from dokka am: 7b150bbe96 am: 77665b0384 am: f3d7b224f7

Original change: https://android-review.googlesource.com/c/platform/external/dokka/+/2666058

Change-Id: I5ca1f99af8b0297e9ff5d684c489dc82982a4792
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>