PLT-8828 - Check that contract is not mixing mainnet and testnet addresses before sending to Runner

[palas]

This PR:

• Adds a linter warning for whenever there are networks from both testnet and mainnet
• Forbids sending contracts to Marlowe Runner when networks mismatch or they are for mainnet (since it is not supported yet)

Pre-submit checklist:

• Branch
  • Tests are provided (if possible)
  • Commit sequence broadly makes sense
  • Key commits have useful messages
  • Relevant tickets are mentioned in commit messages
  • Formatting, materialized Nix files, PNG optimization, etc. are updated
• PR
  • Self-reviewed the diff
  • Useful pull request description
  • Reviewer requested