Fix `config.ts` not loading in Jetbrains Editors

[LLukas22]

Description

Fallback to a file:// url on windows if we failed to import the config.ts.

This fixes the following error when using Continue with jetbrains editors:

[info] Starting Continue core...
[2024-09-27T09:30:19] [info] Starting Continue core... 
[2024-09-27T09:30:19] Setup 
[2024-09-27T09:30:19] Core started 
[2024-09-27T09:30:20] Error loading config.ts:  Error [ERR_UNSUPPORTED_ESM_URL_SCHEME]: Only URLs with a scheme in: file, data are supported by the default ESM loader. On Windows, absolute paths must be valid file:// URLs. Received protocol 'c:'
[2024-09-27T09:30:21] Indexing: 0.0% complete, elapsed time: 0s, NaN file/sec 

Checklist

• [x] The base branch of this PR is dev, rather than main
• [x] The relevant docs, if any, have been updated or created