Load PrometheusProperties at registry initialization

Previously, the loading would happen when the classloader did static initialization on PrometheusProperties, which means the properties loading could have happened before the construction of the specific PrometheusMeterRegistry instance and not contain any changes between then.

implementations/micrometer-registry-prometheus/src/main/java/io/micrometer/prometheusmetrics/PrometheusMeterRegistry.java

@@ -26,8 +26,7 @@
 import io.micrometer.core.instrument.internal.DefaultGauge;
 import io.micrometer.core.instrument.internal.DefaultMeter;
 import io.micrometer.core.instrument.util.TimeUtils;
-import io.prometheus.metrics.config.ExporterProperties;
-import io.prometheus.metrics.config.PrometheusProperties;
+import io.prometheus.metrics.config.PrometheusPropertiesLoader;
 import io.prometheus.metrics.expositionformats.ExpositionFormats;
 import io.prometheus.metrics.model.registry.PrometheusRegistry;
 import io.prometheus.metrics.model.snapshots.*;
@@ -67,9 +66,8 @@
  */
 public class PrometheusMeterRegistry extends MeterRegistry {
 
-    private final ExporterProperties exporterProperties = PrometheusProperties.get().getExporterProperties();
-
-    private final ExpositionFormats expositionFormats = ExpositionFormats.init(exporterProperties);
+    private final ExpositionFormats expositionFormats = ExpositionFormats
+        .init(PrometheusPropertiesLoader.load().getExporterProperties());
 
     private final PrometheusConfig prometheusConfig;