fix: issue where custom-networks defaulted to forked-providers when they were not forked networks.

[antazoey]

What I did

When using a provider that isn't node for a non-forked custom network would still use forked provider version.

How I did it

• Notice both classes were registering
• Add condition to make sure the correct class was registering

How to verify it

foundry:
  blast:
    mainnet-tenderly:
      uri: "https://[REDACTED]"

networks:
  custom:
     - name: mainnet-tenderly
       chain_id: 69420
       ecosystem: blast
       base_ecosystem_plugin: optimism
       default_provider: foundry

connect:

ape console --network blast:mainnet-tenderly:foundry

Checklist

• All changes are completed
• New test cases have been added
• Documentation has been updated