Remove legacy CIDs

[ligi]

this is a follow-up for #6386
There are now legacy CIDs that are bigger than 250kb so we could introduce that limit and still have a CI passing. In the long run we should either remove these icons or reduce their size to fit that limit.

[farbodfar121]

Tank you

[ramykatour]

Hello, I added the chain, but it is still not showing on the website.
https://chainid.network/