Update #hashCode & #equals with mUnderlyingNetworkPriorities

Update VcnGatewayConnectionConfig to consider
mUnderlyingNetworkPriorities in #hashCode and #equals methods

Rename #setAllowedPlmnIds and #getAllowedPlmnIds
to #setAllowedOperatorPlmnIds and #getAllowedOperatorPlmnIds

Bug: 206044122
Test: atest FrameworksVcnTests(new tests), CtsVcnTestCases
Change-Id: Id16d88024bbb7ef275da0304f2dde1413a18de10