APC: Update the string to warn about the audio capture

The warning was only mentioning the screen being captured, as the
audio can now also be capture, it has to be added to the user message
warning.

Test: display the popup with the message
Bug: 128908023
Change-Id: I96f024b455a680eb578699c0c509518645f50f5e
Signed-off-by: Kevin Rocard <krocard@google.com>