Gate binary data on the role's client/state object

[maximmaxim345]

Since role objects became optional per client/state message, a client can satisfy "has sent its initial client/state" with available alone and deliver the player object later on activation. The binary-data gate in messaging.md therefore opened before the server knew output_delay_ms, required_lead_time_ms, or min_buffer_ms.

The gate now requires the role's client/state object before that role's binary data. All built-in roles that receive binary data define one, so only application-specific roles without a state object fall back to the initial client/state. This matches the stream/start rule that waits for the activation update before starting a role's stream.

[kahrendt]

Looks good!