`Date` in `fromJSON` being parsed into Timestamp instead of Date

The `fromJSON` of `/cosmos.base.tendermin.v1beta1.Header` is generated with an error for the `time` key:

```ts
time: isSet(object.time) ? fromJsonTimestamp(object.time) : undefined,
```
```
Type 'Timestamp | undefined' is not assignable to type 'Date | undefined'.
Type 'Timestamp' is missing the following properties from type 'Date': toDateString, toTimeString, toLocaleDateString, toLocaleTimeString, and 37 more.ts(2322)
types.ts(51, 3): The expected type comes from property 'time' which is declared here on type 'Header'
(property) Header.time: Date
```

while to `toJSON` function is generated correctly:

```ts
message.time !== undefined && (obj.time = message.time.toISOString());
```

`Header`'s `time` field is a Date, but `fromJSON` seems to be outputting a `Timestamp` via `fromJsonTimestamp` instead of a `Date`. The JSON representation is the Date's ISO string.