clear alarm node: default script changed to avoid infinite metadata grow

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/action/TbClearAlarmNodeConfiguration.java

@@ -25,10 +25,18 @@ public class TbClearAlarmNodeConfiguration extends TbAbstractAlarmNodeConfigurat
     @Override
     public TbClearAlarmNodeConfiguration defaultConfiguration() {
         TbClearAlarmNodeConfiguration configuration = new TbClearAlarmNodeConfiguration();
-        configuration.setAlarmDetailsBuildJs("var details = {};\n" +
+        configuration.setAlarmDetailsBuildJs("" +
+                "//***DO NOT CHANGE THIS LINES***\n" +
+                "var details = {};\n" +
                 "if (metadata.prevAlarmDetails) {\n" +
                 "    details = JSON.parse(metadata.prevAlarmDetails);\n" +
+                "    //remove prevAlarmDetails from metadata\n" +
+                "    metadata.delete('prevAlarmDetails')\n" +
+                "    //now metadata is the same as it comes to this rule node" +
                 "}\n" +
+                "//***PLACE YOU CODE BELOW***\n" +
+                "\n" +
+                "\n" +
                 "return details;");
         configuration.setAlarmType("General Alarm");
         return configuration;