The switch to using agl-service-audiomixer missed a scaling to 0.0 - 1.0
for the value requested when changing the master volume slider, add that
to fix it. Also, change the displayed name back to "Master Volume" to
match what it now represents with PipeWire.
Bug-AGL: SPEC-2788
Signed-off-by: Scott Murray <scott.murray@konsulko.com>
Change-Id: I2fb94d161499b759540105958bcb3d6f5da1884f