Update participants state on raise_hands_disabled event

Fixes the

Issue 1 : Raised hand icon remains visible for participants after moderator disables raised hands of the

opentalk/product/tickets#343 (closed)

New roomserver does not update every participant on disabling raise hands explicitly. Instead it sends a general raise_hands_disabled event.

Frontend must take care of the participant state update itself.

Logs and/or screenshots

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