[DVX-889] isolate axios instance to prevent global interceptor side effects

[penelopus]

Description

refactor: isolate axios instance to prevent global interceptor side effects

• fixes bug in Polygon client library where subsequent calls return undefined even though the network request succeeds
  • first fetch works and renders as expected
  • subsequent fetches retrieve data from API successfully (verified in browser network inspector), but API returns undefined

Related Issue

https://linear.app/mod-labs/issue/DVX-889/dev-fix-bug-w-subsequent-fetches-in-client-js-library

• discovered while testing API w/ demo — see gist for code example

Motivation and Context

bugfix

How Has This Been Tested?

tested locally w/ fix

• with this branch, run npm pack to generate a *.tgz
• in sample project (using gist referenced above), link to local package w/ npm install <path_to_tgz>
• verify initial and subsequent data fetches return expected payload (no undefined)

[mpatel18]

Appreciate the find on the pagination, I thought something like this wasn't happening when making the next_url calls.

[mpatel18]

👍🏽