Problem: We pass grpc context down to applier in readonly serializable txn.
This context can be cancelled for example due to timeout.
This will trigger panic inside applyTxn
Solution: Only panic for transactions with write operations
fixes https://github.com/etcd-io/etcd/issues/14110
main PR https://github.com/etcd-io/etcd/pull/14149
Signed-off-by: Bogdan Kanivets <bkanivets@apple.com>
