Rename getVpnRequiresValidation to isVpnValidationRequired

Update API name from getVpnRequiresValidation to
isVpnValidationRequired according to API review feedback.

Test: atest FrameworksNetTests
Bug: 220129160
Change-Id: I1025f4c35b320c14e872eaffd7ed82658a5f3d0c
3 files changed