The tests were relying on the `RulesetID` being set to 0 in the example
beatmap, even though the ruleset *instance* was set to ID 5.
This explicitly adds that 0 value to show intent, and also removes the
incorrect specification of 5 (which would cause the convert filter tests
to fail).
Also updates the filter code to use `OnlineID`, which is required in
realm changes.
This has been wrong from the outside, but hidden by the fact that the
default values are equal. I've changed to MD5Hash which actually asserts
that the correct beatmap has likely arrived.
Found this in my realm changes, where it fails due to the beatmap ID
being a differing Guid in each case.