Allow multiple model configs with the same provider and model name to be available simultaneously.

[Haru-L]

Is your feature request related to a problem? Please describe.
When configuring multiple models using the OpenAI format, if the model names are the same, only one of them will be displayed in the model list. This is problematic when I need multiple external providers to ensure availability.
A possible reason is that the system uses the index generated by the function getModelKeyFromModel to filter model configurations (src/settings/model.ts:587-589).

export function getModelKeyFromModel(model: CustomModel): string {  
  return `${model.name}|${model.provider}`;  
}

Describe the solution you'd like
Introduce the Display Name into getModelKeyFromModel

Describe alternatives you've considered
N/A

Additional context
N/A