Add Javadoc @Since for new PrometheusScrapeEndpoint constructor

See gh-42406

spring-boot-project/spring-boot-actuator/src/main/java/org/springframework/boot/actuate/metrics/export/prometheus/PrometheusScrapeEndpoint.java

@@ -69,6 +69,7 @@ public PrometheusScrapeEndpoint(PrometheusRegistry prometheusRegistry) {
  * @param prometheusRegistry the Prometheus registry to use
  * @param exporterProperties the properties used to configure Prometheus'
  * {@link ExpositionFormats}
+ * @since 3.3.1
  */
  public PrometheusScrapeEndpoint(PrometheusRegistry prometheusRegistry, Properties exporterProperties) {
  this.prometheusRegistry = prometheusRegistry;