Prometheus: Annotation query filtering values less then 1 (#53969)

* prevent annotation query from filtering values less then 1
* unit tests were asserting that gaps in data (0 value) are removed from annotation, update filter to exclude 0

public/app/plugins/datasource/prometheus/datasource.tsx

@@ -796,7 +796,7 @@ export class PrometheusDatasource
         timeValueTuple.push([timeStampValue, valueValue]);
       });
 
-      const activeValues = timeValueTuple.filter((value) => value[1] >= 1);
+      const activeValues = timeValueTuple.filter((value) => value[1] > 0);
       const activeValuesTimestamps = activeValues.map((value) => value[0]);
 
       // Instead of creating singular annotation for each active event we group events into region if they are less