Setting conflicting BASE_URL and ENVIRONMENT variables doesn't throw a helpful error

[louispt1]

Context

If you set your ENVIRONMENT to 2025-01 and your BASE_URL to engine.energytransitionmodel.com/api/v3, calls to myetm will work correctly via passthrough, but calls that require the engine will fail with a vague error message (404 not found).

Proposed solution

If users set conflicting settings via their environment variables, a warning should be shown.
--> Alternative solution: Retire the BASE_URL env var. It is redundant.