Hi,
To remove this icon you would need to set the 'telephony type' to 'Audio/Video Disabled' in the properties of the Lync user account. (Either through the Lync control panel or through the management shell under the Set-CsUser sub set)
Doing so would also remove the video icon from the pop out menu, and naturally prevent users from making audio or video calls.
If you're asking if there is a way to remove this icon from the Lync desktop client whilst retaining the PC to PC calling functionality, then I do not think this can be done natively in Lync.
Kind regards
Ben
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