JSON environment is not saved when json format becomes valid for the first time[INS-5894]

[cwangsmv]

Reproduce Step:

1. Existing JSON environment:

{"foo": "bar"}

2.Insert a new row(Invalid JSON since comma is missing for the first line)

{
"foo": "bar"
"foo1": "bar"
}

3.Add the missing comma and close the editor

{
"foo": "bar",
"foo1": "bar"
}

4.The environment has not been saved

The root cause is that when json becomes valid for the first time, the isValid() ref still returns the false since error state is not updated yet.
Add a new ref to save the error message and isValid() ref will use the ref to detect if the json content is valid or not.