Enhancement for the Exception handling

Some unexpected Errors could lead the page blank white screen;

Case:

item data:

```json
{"id":"fixedTab","name":"FlinkSQL","data":{"value":"select * from abc;e","language":"flinksql"},"value":{"code":"select * from abc;e","message":"extraneous input 'E' expecting ","startLineNumber":1,"startColumn":18,"endLineNumber":1,"endColumn":1,"status":8}}
```

```typescript
molecule.problems.addProblems(item)

```
The item lacks the `children` property:


This Picture comes from ProblemsService added some unknown or incorrect type of data.