Fix API review issues for 5G Slicing feature

- Rename SlicingConfig and SlicingException to
  NetworkSlicingConfig and NetworkSlicingException

Bug: 183714964
Test: atest TelephonyManagerTest#testGetNetworkSlicingConfiguration
Change-Id: Ib6cda75e5800f23a18b173349549e612485019f8
1 file changed