New model wizard should not add duplicate models

[fbricon]

Validations

• [X] I believe this is a way to improve. I'll try to join the Continue Discord for questions
• [X] I'm not able to find an open issue that requests the same enhancement

Problem

If I add an Ollama/Autodetect provider via the Model wizard, Continue doesn't check the exact same model configuration exists and then blindly adds a second model.

Solution

If the exact same model configuration is already set in the config.json file, continue should either ignore it, or ask the user to add it anyway

[sestinj]

@fbricon good idea! Made the change here, to be included in the next releases