Fix: Improve localStorage error handling in storageHelper.js

[FrankOHara43]

Description

After logging into the UI page hydration error was being rendered due to the localStorage value being missing or malformed.

Changes

-Added checks for null, undefined, and empty string values from localStorage.getItem(key).
-Wrapped JSON.parse in a try-catch block to prevent runtime errors if the stored value is not valid JSON.
-Added error logging for JSON parsing failures.

[BUDDHABHUSHAN23]

Hi @FrankOHara43 — I independently reproduced both of these issues today while setting up FOSSologyUI locally.
Tested on:

FOSSology backend v4.6.0.95 via Docker
Confirmed api/v2/tokens returns 400 with snake_case fields, 201 with camelCase
Confirmed storageHelper crashes with "undefined is not valid JSON" after login

Both fixes look correct. The camelCase change in src/api/auth.js resolves the v2 token issue and the try-catch in storageHelper.js resolves the post-login hydration crash.
Tested and verified locally ✅

[FrankOHara43]

Thank you for testing it out!!!