Add test for muted plaintext log behavior

This test verifies that logs below the ERROR level are properly muted when plaintext logging is enabled without JSON formatting. It ensures that log output adheres to the configured log level settings.

log_test.go

@@ -57,6 +57,15 @@ func Test_PlainTextLogs(t *testing.T) {
 	SetLogLevel(INFO)
 }
 
+func Test_MutedPlainTextLogs(t *testing.T) {
+	InitStoneLog(ERROR, false, true)
+	Trace("This is a trace log")
+	Debug("This is a debug log")
+	Observation("This is an observation log")
+	Hypothesis("This is a hypothesis log")
+	Failure("This is a failure log")
+}
+
 func Test_JSONLogs(t *testing.T) {
 	InitStoneLog(TRACE, true, false)
 	Trace("This is a trace log")