[Tmds.DBus.Protocol] Don't respond on any method_call

[shimr12]

Mostly for a use case of working as a monitor after calling BecomeMonitor.

Responding for these messages as a monitor isn't allowed and causes the dbus service to disconnect us

[tmds]

@shimr12 sorry for the unresponsiveness. It's been a busy few weeks for me, but it should be a bit calmer now.

What do you think about adding a BecomeMonitorAsync to Connection

Its signature would be something like:

ValueTask BecomeMonitorAsync(
    IEnumerable<MatchRule>? rules,
    Action<Exception?, Message, object?> handler,
    object? handlerState = null,
    bool emitOnCapturedContext = true);

Would that be usable for you?

If it looks good, do you want to implement it, or do you prefer I look into it?

The implementation would include no longer replying to messages when this method got called.

[shimr12]

not sure I will find time to do these changes in the next weeks, so would prefer if you could add this change :)

[tmds]

Closing in favor of #217.