[Thread] pre-grant all permissions for ThreadNetworkControllerServiceTest

Existing ThreadNetworkControllerService tests are using RunAsShell to
grant the permissions for indivitual APIs. Given the permission checks
are tested in the CTS tests, this is not very useful with the overhead
of complicating the testing code. Instead, this CL grants all the
permissions in setUp() with spy-ed Context.

This commit also fixes the issue in b/326793058 that the tests doesn't
run on a U device where the THREAD_NETWORK_PRIVILEGED permission doesn't
exist.

Bug: 326793058
Test: m ThreadNetworkUnitTests
Change-Id: I477cf30d737969ccf12180eae48d3b8fd6ed4a51