test_helpers: Remove noop.
test_helpers: Remove noop.

`BaseNotes(str, str).get_notes` does not do anything here.
It was introduced in
https://github.com/zulip/zulip/commit/53888e5a26ce0ebfc3cb56877cee363a3d9790d9
by unintendedly.

Signed-off-by: Zixuan James Li <74923aee05c23ca90566381b5d6b0cd9451b6054@gmail.com>

zulip/zulip,rht/zulip,andersk/zulip,andersk/zulip,rht/zulip,andersk/zulip,zulip/zulip,zulip/zulip,andersk/zulip,rht/zulip,andersk/zulip,zulip/zulip,andersk/zulip,rht/zulip,rht/zulip,zulip/zulip,rht/zulip,andersk/zulip,zulip/zulip,rht/zulip,zulip/zulip