Only capture stacktrace for snapshot probes (#6955)

For any log probes we recorded stacktrace while this is useless and
wasteful for template log only

Author: jpbempel

dd-java-agent/agent-debugger/src/main/java/com/datadog/debugger/probe/LogProbe.java

@@ -534,7 +534,9 @@ protected void commitSnapshot(Snapshot snapshot, DebuggerSink sink) {
      * - ProbeDefinition.commit()
      * - DebuggerContext.commit() or DebuggerContext.evalAndCommit()
      */
-    snapshot.recordStackTrace(5);
+    if (isCaptureSnapshot()) {
+      snapshot.recordStackTrace(5);
+    }
     sink.addSnapshot(snapshot);
   }
 

dd-java-agent/agent-debugger/src/test/java/com/datadog/debugger/agent/LogProbesInstrumentationTest.java

@@ -4,6 +4,7 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 import static utils.InstrumentationTestHelper.compileAndLoadClass;
@@ -63,6 +64,7 @@ public void methodPlainLog() throws IOException, URISyntaxException {
     Assertions.assertEquals(3, result);
     Snapshot snapshot = assertOneSnapshot(listener);
     assertCapturesNull(snapshot);
+    assertTrue(snapshot.getStack().isEmpty());
     assertEquals("this is log line", snapshot.getMessage());
   }