Fixed normal bug EXT-5116 (Voice notification should display on top of IM window, not under.)

Replaced sending voice notifications to front (in floater view) with adding them to popup view.
In this case Voice Notifications are shown on top even IM window has focus. And Resident can continue enter the text when Voice notification is shown.

Reviewad by Vadim at https://codereview.productengine.com/secondlife/r/120/

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branch : product-engine