Sorted submissions are not paginated correctly

[FrankApiyo]

Environmental Information

• Onadata version: v2.5.7

Problem description

Submissions on data endpoint are not paginated correctly when you pass sort query parameter

Without sort query parameter:

With sort query parameter:

Expected behavior

Pagination query parameters should work the same with or without the order query parameters

[WinnyTroy]

From testing this, I would like to note the following:

The API does successfully return paginated, sorted data (Ascending and Descending). The request you should be making should ideally be:

https://api.ona.io/api/v1/data/381370.json?page_size=3&page=1&sort={"_submission_time":-1}
https://api.ona.io/api/v1/data/381370.json?page_size=3&page=1&sort={"date_created":-1}

Sorting a specific field within the submitted data occurs successfully as detailed here, but this returns all fields within the submitted data for the form.
If your goal is to fetch paginated, sorted fields in the submitted data, pagination query params are not supported at the moment i.e page_size and page, but you could do:
https://api.ona.io/api/v1/data/381370.json?limit=10&sort={"_submission_time":-1}&fields=["_submission_time", "_id"]
The limit query param has been detailed here

I'll be adding tests to confirm the above scenerios work as expected and updating the documentation appropriately

Cc: @denniswambua ua @FrankApiyo