Updated "postman-collection" usage to be specific to part of module being used.

[VShingala]

Overview

This PR updates "postman-collection" version used to latest. We're also now making sure that we're only requiring the part of SDK that's used in codebase by requiring specific files.

This means if we use say Response from postman-collection module then instead of requiring it like below,

const { Response } = require('postman-collection');

we will be requiring Response from specific module exporting it like below.

const { Response } = require('postman-collection/lib/collection/response');