Cleanup minor things in whitebox metrics code

Specifically:
- remove @RequestScope from EppMetric since it's only for components
- fix to call the better overload of toBigqueryTimestamp
- use the same UUID provider for BigQueryMetricsEnqueuer that already exists for
  the VerifyEntityIntegrityStreamer
- minor cleanup in VerifyEntityIntegrityStreamer (inject projectId vs whole env)

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=132721794

java/google/registry/monitoring/whitebox/WhiteboxModule.java

@@ -65,7 +65,8 @@ public class WhiteboxModule {
   }
 
   @Provides
-  static Supplier<String> provideIdGenerator() {
+  @Named("insertIdGenerator")
+  static Supplier<String> provideInsertIdGenerator() {
     return new Supplier<String>() {
       @Override
       public String get() {