fix: issue where plugin config loading error was not shown

[antazoey]

What I did

I had my config set up with some environment variables that did not exist, and i noticed that instead of Ape crashing where it was supposed to, my error s were dropped and the configs were turned to regular PluginConfig and i got attribute errors within the plugin instead, kinda weird...

How I did it

Removed duplicate get_config method that hid the errors for no reason. instead, let ConfigManager run ApeConfig.get_config and the error shows up correctly.

How to verify it

foundry:
  fork:
    shibarium:
      mainnet:
        block_number: {asdf}

try to use foundry

Checklist

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