fix(test): register requestFilesContent in InstrumentationGatewayTest event coverage

Author: jandro996

internal-api/src/test/java/datadog/trace/api/gateway/InstrumentationGatewayTest.java

@@ -240,6 +240,10 @@ public void testNormalCalls() {
     assertEquals(
         Flow.Action.Noop.INSTANCE,
         cbp.getCallback(events.requestFilesFilenames()).apply(null, null).getAction());
+    ss.registerCallback(events.requestFilesContent(), callback);
+    assertEquals(
+        Flow.Action.Noop.INSTANCE,
+        cbp.getCallback(events.requestFilesContent()).apply(null, null).getAction());
     ss.registerCallback(events.fileWritten(), callback);
     cbp.getCallback(events.fileWritten()).apply(null, null);
     assertEquals(Events.MAX_EVENTS, callback.count);
@@ -331,6 +335,9 @@ public void testThrowableBlocking() {
     ss.registerCallback(events.requestFilesFilenames(), throwback);
     assertEquals(
         Flow.ResultFlow.empty(), cbp.getCallback(events.requestFilesFilenames()).apply(null, null));
+    ss.registerCallback(events.requestFilesContent(), throwback);
+    assertEquals(
+        Flow.ResultFlow.empty(), cbp.getCallback(events.requestFilesContent()).apply(null, null));
     ss.registerCallback(events.fileWritten(), throwback);
     cbp.getCallback(events.fileWritten()).apply(null, null);
     assertEquals(Events.MAX_EVENTS, throwback.count);