Add "hasAnyIndices" method to Metadata

If all we want to know is whether the cluster has any indices, then
this new method is more efficient than using the existing
"getTotalNumberOfIndices" method

Author: tvernum

server/src/main/java/org/elasticsearch/cluster/metadata/Metadata.java

@@ -550,6 +550,18 @@ public int getTotalNumberOfIndices() {
         return indexCount;
     }
 
+    /**
+     * @return {code true} if there are any indices in any project in this cluster
+     */
+    public boolean hasAnyIndices() {
+        for (ProjectMetadata project : projects().values()) {
+            if (project.indices().isEmpty() == false) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     /**
      * @return The oldest {@link IndexVersion} of indices across all projects
      */

server/src/main/java/org/elasticsearch/cluster/routing/allocation/NodeAllocationStatsAndWeightsCalculator.java

@@ -70,7 +70,7 @@ public Map<String, NodeAllocationStatsAndWeight> nodesAllocationStatsAndWeights(
         ClusterInfo clusterInfo,
         @Nullable DesiredBalance desiredBalance
     ) {
-        if (metadata.indices().isEmpty() == false) {
+        if (metadata.hasAnyIndices()) {
             // must not use licensed features when just starting up
             writeLoadForecaster.refreshLicense();
         }

server/src/main/java/org/elasticsearch/cluster/routing/allocation/allocator/BalancedShardsAllocator.java

@@ -147,7 +147,7 @@ public BalancedShardsAllocator(ClusterSettings clusterSettings, WriteLoadForecas
 
     @Override
     public void allocate(RoutingAllocation allocation) {
-        if (allocation.metadata().indices().isEmpty() == false) {
+        if (allocation.metadata().hasAnyIndices()) {
             // must not use licensed features when just starting up
             writeLoadForecaster.refreshLicense();
         }