Fixed bug with REST API data representation for telemetry plugin

extensions-core/src/main/java/org/thingsboard/server/extensions/core/plugin/telemetry/SubscriptionManager.java

@@ -291,7 +291,6 @@ public class SubscriptionManager {
                     } else {
                         log.trace("[{}] Remote subscription is now handled on new server address: [{}]", s.getWsSessionId(), newAddress);
                         subscriptionIterator.remove();
-
                         //TODO: onUpdate state of subscription by WsSessionId and other maps.
                     }
                 }

extensions-core/src/main/java/org/thingsboard/server/extensions/core/plugin/telemetry/handlers/TelemetryRestMsgHandler.java

@@ -139,7 +139,12 @@ public class TelemetryRestMsgHandler extends DefaultRestMsgHandler {
             public void onSuccess(PluginContext ctx, List<TsKvEntry> data) {
                 Map<String, List<TsData>> result = new LinkedHashMap<>();
                 for (TsKvEntry entry : data) {
-                    result.put(entry.getKey(), data.stream().map(v -> new TsData(v.getTs(), v.getValueAsString())).collect(Collectors.toList()));
+                    List<TsData> vList = result.get(entry.getKey());
+                    if (vList == null) {
+                        vList = new ArrayList<>();
+                        result.put(entry.getKey(), vList);
+                    }
+                    vList.add(new TsData(entry.getTs(), entry.getValueAsString()));
                 }
                 msg.getResponseHolder().setResult(new ResponseEntity<>(result, HttpStatus.OK));
             }