Update store.browser.ts to handle window.localStorage access error

[BenMuschol-at]

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

🐛 Bug fix

• What is the current behavior? (You can also link to an open issue here)

window.localStorage crashes in an iframe with an Access Denied error. The code is already resilient to localStorage not existing, it's just not resilient to localStorage throwing an error. This PR includes a minor code structure change so that it handles this case.

• What is the new behavior (if this is a feature change)?

Does not crash in iframes, properly falls back to other storage

• Other information:

[heiglandreas]

This is a vital change for our use-case as well.

Steps to reproduce:

In Firefox 119 set the browser privacy to "Custom" and set blocked "Cookies" to "All cross-site cookies".

Embed the filestack-code in a website that is then embedded in an iFrame on a different domain. Now accessing the localStorage will fail with error "Error: Failed to read the 'localStorage' property from 'Window': Access is denied for this document" or similar.