Convert the handleLoginForm to async and await for fetch api

[emmanuelonwukwe]

I converted the handleLoginForm function of the src/App.js file to async so we can await for the fetch api response incase the user needs to make use of the response data.

[Dhinesh-07]

I suggest to use async and await function for fetch api, the code which @emmanuelonwukwe was changed was best approach to handle the api