[remote_config] add method to get json values

[mu-neeraj]

Is your feature request related to a problem? Please describe.
From firebase console you can set json value to a key. Flutter sdk does not expose any method to retrieve json type values. It only exposes methods to fetch primitive type values.

Describe the solution you'd like
Flutter sdk to should expose a method

Map<String, dynamic> getJson(String key)

[Patryczon]

Same problem here :(

[bounty1342]

You can fetch the String value of the json and them json.decode() it.

But there is an issue at the moment : #2074

Please drop a like on it, so it gets prioritized 👍

[Ehesp]

So the native SDKs (web included) don't return a getJson method. I'll have a think about this one, however to actually check whether it's JSON we'd need to try catch the getString value when decoding it, which I'm not sure is ideal since it'd have to happen every time.