Dialer: replace the blurry background picture of overflow button

Resized from xxhdpi resource. I'm wondering why the one in AOSP is
so blurry...

Change-Id: I5e0e3aa262df88dd2cff91397e7efaf0f496ecc5
Dialer: deblur fab_blue.png

One of my users is reporting this kind of problem
all around the dialer app...

Zoom in and we'll see the edge of button in
original picture is not clear. The new one is
much more smoother.

Change-Id: I92e48166abcaa22e7ad73f0859ade09bafa1b2bb