Update Superhero Wallet description to correct wording discrepancies (all platforms). Fix extension icon.

[onvisions]

1. Extension description needs wording improvement for better consistency and fixing some styling and semantic errors. Issue listed below:

Wording fixes to be applied to web stores (both Chrome and Firefox) and mobile app stores (App Store and Google Play).

2. Broken scaling ratio of the extension diamond icon is observed in Firefox (see screenshot). Same problem exists on the preloading screen of the mobile apps. Related to: https://github.com/superhero-com/superhero-wallet/issues/2964

@smaroudasunicorn, suggested text updates and fixes will need PO approval.

[onvisions]

@smaroudasunicorn

The above user story is already outdated but there are new issue I have found while working on the update of Superhero Wallet screenshots for the app and web stores.

I'm attaching a screenshot of the current description with my comments:

[onvisions]