Resolve CUJ test isolation issues

CallSequencingManagedHoldRestrictionTest was failing due to test
isolation issues emanating from CallSequencingBasicCallTests. The tests
weren't properly cleaning up the static fields being used for test
verification which were causing subsequent tests to fail. Ensure that
everything gets reset after each test verification.

Bug: 395862818
Flag: EXEMPT test fix
Test: atest CtsTelecomCujTestCases
Change-Id: Iaa8ecd7519ab1523267de6e220d478d09c37fdaf
1 file changed