Lower the volume for tone generator tones in Telecom.

Although 30% seems low, these tones are VERY loud and grating.
This lowers the tone volume so it is not as piercing when you have your
ear to the phone.

Test: Manual test with test app to verify tone generator volume.
Fixes: 262159207
Change-Id: I94b19dea7e4fe1ac76f8eb5492eab92e2d832679