Tech Debt: Remove usage of axios in postman feature

[yong-jie]

Is your feature request related to a problem? Please describe.
The codebase is using cross-fetch. The introduction of axios was a quick way to get http requests sent in a more familiar interface to the engineer. #1912

Describe the solution you'd like
We could change the axios call into a cross-fetch one some time after everything stables.

Describe alternatives you've considered
Back then there were problems with HTTP request libraries regarding browser-compat, making it necessary for us to use cross-fetch. If this problem is no longer still there, we can also consider taking a greater effort to migrate over from cross-fetch to axios.

Additional context
The postman feature was a quick fix that introduces email-OTP fallback.