Revert "TableMetricsManager#getSizeHistogramsForAllTables() is returning empty map (#1727)"

This reverts commit f97c19bda2046db922f0375460e0ee5c457851b0.
diff --git a/phoenix-core/src/main/java/org/apache/phoenix/monitoring/TableMetricsManager.java b/phoenix-core/src/main/java/org/apache/phoenix/monitoring/TableMetricsManager.java
index 24aaaea..142d391 100644
--- a/phoenix-core/src/main/java/org/apache/phoenix/monitoring/TableMetricsManager.java
+++ b/phoenix-core/src/main/java/org/apache/phoenix/monitoring/TableMetricsManager.java
@@ -323,7 +323,6 @@
         Map<String, List<HistogramDistribution>> map = new HashMap<>();
         for (Map.Entry<String, TableClientMetrics> entry : tableClientMetricsMapping.entrySet()) {
             TableHistograms tableHistograms = entry.getValue().getTableHistograms();
-            map.put(entry.getKey(), tableHistograms.getTableSizeHistogramsDistribution());
         }
         return map;
     }