Fix the broken test

[rayworks]

Original error message when running Robolectric test:

failed to configure com.example.android.uamp.media.library.MusicSourceTest.whenReady_errorContinues: Package targetSdkVersion=30 > maxSdkVersion=28
java.lang.IllegalArgumentException: failed to configure com.example.android.uamp.media.library.MusicSourceTest.whenReady_errorContinues: Package targetSdkVersion=30 > maxSdkVersion=28
	at org.robolectric.RobolectricTestRunner.getChildren(RobolectricTestRunner.java:240)
	at org.junit.runners.ParentRunner.getFilteredChildren(ParentRunner.java:534)
	at org.junit.runners.ParentRunner.getDescription(ParentRunner.java:400)
	at org.junit.runners.model.RunnerBuilder.configureRunner(RunnerBuilder.java:81)
	at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:72)
	at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:37)
	at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:70)
	at org.junit.internal.requests.ClassRequest.createRunner(ClassRequest.java:28)
	at org.junit.internal.requests.MemoizingRequest.getRunner(MemoizingRequest.java:19)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:78)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
	at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
	at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
	at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
	at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
	at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
	at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:118)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
	at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
	at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
	at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:412)
	at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
	at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
	at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.IllegalArgumentException: Package targetSdkVersion=30 > maxSdkVersion=28
	at org.robolectric.plugins.DefaultSdkPicker.configuredSdks(DefaultSdkPicker.java:118)
	at org.robolectric.plugins.DefaultSdkPicker.selectSdks(DefaultSdkPicker.java:69)
	at org.robolectric.RobolectricTestRunner.getChildren(RobolectricTestRunner.java:206)
	... 38 more