Implement ranked play chat filter

[zihadmahiuddin]

I think this is good enough until the new design for ranked play is added.

Closes #37424

[bdach]

Diff looks okay I suppose but not sure how this was tested to work in practice. Tests would be nice to see.

For one thing testing on dev I notice a slight flicker of the text when the resolution occurs. Probably from clearing the text flow and adding text afresh. Not sure it can be avoided easily, but would be good if it could be.

[zihadmahiuddin]

I tested manually, dev server doesn't seem to have any chat filters, so I just temporarily added

message.Content = "nah";

to https://github.com/ppy/osu/blob/master/osu.Game/Online/Chat/WebSocketChatClient.cs#L133 to simulate receiving a different response from the server.
I'll try to add some tests, but not sure what to do about the flickering. I don't even notice it on my display, or it might just be my eyes.

[zihadmahiuddin]

Not sure if the tests are up to standard, let me know if they're wrong.