Update READ_PHONE_STATE doc to remove reference to phone number

Now that READ_PHONE_STATE is an install permission apps targeting
R+ will no longer have access to the device's phone number(s) with
this permission. This commit updates the framework's AndroidManifest
to remove the reference indicating this permission grants access to
the device phone number.

Bug: 136160623
Test: Builds
Change-Id: I681c38aa8fe70adb185db7423b81da2b8bbdc2e7