docs(isc-wiki): remove duplicates for EVM and ShimmerEVM Testnet

[Ginowine]

Description of change

The IOTA EVM Testnet and ShimmerEVM Testnet have duplicates on the Networks and Chains page. This PR removes the duplicates.

Links to any relevant issues

fixes issue #1605 .

Type of change

• Documentation Enhancement

Change checklist

• [x] I have followed the contribution guidelines for this project
• [x] I have performed a self-review of my own changes
• [x] I have made sure that added/changed links still work

[lucas-tortora]

@vivekjain23 , could you please review this?

[github-actions[bot]]

This pull request has been deployed to Vercel.

Latest commit: 60f31d6f7d864d4a3469b19b1ae8efa1d348baff

:white_check_mark: Preview: https://iota-wiki-dnuked4mq-iota1.vercel.app