Remove CQ for unsupported branch chrome/m103

Change-Id: I8000918e9a4d4fbbf70722b2159bbe693cdad471
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/581937
Reviewed-by: Eric Boren <borenet@google.com>
Reviewed-by: Rakshit Sharma <sharaks@google.com>