[CS06]Remove hidden API usage of NetworkCapabilities

The connection service will become the mainline module. The mutable
NetworkCapabilities is deprecated, and the NetworkCapabilities should
be built through their Builder instead.

Bug: 170598012
Tag: #feature
Test: atest BluetoothInstrumentationTests
Change-Id: I5f88389583d9ecfba694b82acbd150805e49d9d5