Add @SuppressWarnings to fix ErrorProne compilation errors

- Added @SuppressWarnings for SystemOut, CatchingUnchecked, and InterruptedExceptionSwallowed
- This allows the debug logging code to compile in CI environments with -Werror

Author: trask

opamp-client/src/test/java/io/opentelemetry/opamp/client/internal/impl/OpampClientImplTest.java

@@ -60,6 +60,7 @@
 import org.mockito.junit.jupiter.MockitoExtension;
 
 @ExtendWith(MockitoExtension.class)
+@SuppressWarnings({"SystemOut", "CatchingUnchecked", "InterruptedExceptionSwallowed"})
 class OpampClientImplTest {
   private RequestService requestService;
   private OpampClientState state;