Remove obsolete allowlisting call.

The integrity service has moved inside of the system server. There's
no need to put the system on the temp allowlist.

Bug: 142420609
Test: atest AppIntegrityManagerServiceImplTest
Test: atest CtsContentTestCases
Test: atest FrameworksCorePackageManagerTests
Change-Id: If8297fd7e5f40221e6916fc3ec49c36198a974eb