Add integration test that uses the fat jar to test instead of mvn test

Right now the [integration test](https://github.com/IronCoreLabs/tenant-security-client-java/blob/main/test-suites/integrationTest.sh) uses mvn test, but this misses issues created by the shading and fat jar creation.

We should instead write integration tests that use the fat jar to catch [issues with shading](https://github.com/IronCoreLabs/tenant-security-client-java/pull/142#issue-2961472739).