Remix plugin: Use Sourcify API v2

[manuelwedler]

We should adapt the Remix plugin to use our new API.

[kuzdogan]

Duplicate of #1721

[manuelwedler]

This is for updating the Sourcify API calls not the Etherscan ones

[kuzdogan]

A little last minute but something I thought about after this tweet: https://x.com/CristovaDeny/status/1950543657666478192

I think we should not fully remove the APIv2 from the plugin but make v2 the default and provide option to switch to v1. A lot of the self-hosted Sourcify instances still use v1.

[manuelwedler]

Should be doable 👍