Add test for [set|is]BypassableVpn

Bug: 182963397
Test: 1. atest CtsNetTestCases:NetworkAgentConfigTest
      2. atest CtsNetTestCasesLatestSdk:NetworkAgentConfigTest
Change-Id: I0250a0313d3a7561ab8efa851fbc06f5bce11185
1 file changed