chore: Add implementation for firestore resource

Author: lqiu96

java-datastore/google-cloud-datastore/src/main/java/com/google/cloud/datastore/telemetry/TelemetryConstants.java

@@ -52,7 +52,8 @@ public class TelemetryConstants {
   public static final String RESOURCE_LABEL_DATABASE_ID = "database_id";
   public static final String RESOURCE_LABEL_LOCATION = "location";
   public static final Set<String> DATASTORE_RESOURCE_LABELS =
-      ImmutableSet.of(RESOURCE_LABEL_PROJECT_ID, RESOURCE_LABEL_DATABASE_ID, RESOURCE_LABEL_LOCATION);
+      ImmutableSet.of(
+          RESOURCE_LABEL_PROJECT_ID, RESOURCE_LABEL_DATABASE_ID, RESOURCE_LABEL_LOCATION);
 
   // Resource attribute keys (used on OTel Resource)
   public static final AttributeKey<String> PROJECT_ID_KEY = AttributeKey.stringKey("project_id");

java-datastore/google-cloud-datastore/src/test/java/com/google/cloud/datastore/telemetry/DatastoreCloudMonitoringExporterTest.java

@@ -148,10 +148,14 @@ public void testExportingSumData() {
 
     assertThat(timeSeries.getMetric().getLabelsMap())
         .containsExactly(
-            DATABASE_ID_KEY.getKey(), DATABASE_ID,
-            CLIENT_NAME_KEY.getKey(), this.clientName,
-            CLIENT_UID_KEY.getKey(), this.clientUid,
-            SERVICE_KEY.getKey(), SERVICE_VALUE);
+            DATABASE_ID_KEY.getKey(),
+            DATABASE_ID,
+            CLIENT_NAME_KEY.getKey(),
+            this.clientName,
+            CLIENT_UID_KEY.getKey(),
+            this.clientUid,
+            SERVICE_KEY.getKey(),
+            SERVICE_VALUE);
 
     assertThat(timeSeries.getPoints(0).getValue().getInt64Value()).isEqualTo(fakeValue);