[fix](cache) fix show cache hotspot syntax error (#41519)

fe/fe-core/src/main/java/org/apache/doris/analysis/ShowCacheHotSpotStmt.java

@@ -153,7 +153,7 @@ private String generateQueryString() {
             query = q1.append(q2);
         } else if (metaDataPos == 2) {
             query = new StringBuilder("select partition_id as PartitionId, partition_name as PartitionName"
-            + "FROM " + TABLE_NAME.toString()
+            + " FROM " + TABLE_NAME.toString()
             + " where " +  whereExpr.get(0)
             + " and " + whereExpr.get(1)
             + "group by cluster_id, cluster_name, table_id, "