Add Missing Methods for Integrations

[Cliftonz]

Some endpoints of the following section can't be hit from this SDK.

We would like to ensure that all endpoints can be hit. For this issue, we would like to build out the Integrations

Some of these methods may already exist. 
If so no need to change/update them, just point out that they already exist and we will close the issue.

This is just to bring every SDK we have on par with all the methods available.

Check all the endpoints here and add the missing ones.

[prathamesh-88]

@Cliftonz I'd like to work on this. Can I pick this up?

[prathamesh-88]

@Cliftonz
I am getting error code 401 with the following response:
{"message":"API endpoint not available","error":"Unauthorized","statusCode":401}

For endpoints, /v1/integrations/{channelType}/limit and /v1/integrations/in-app/status
Is this a known issue?