Project ID validation may fail with obscure error when `SCW_DEFAULT_PROJECT_ID` is not defined in Scaleway config

[cyclimse]

In the validation code, we assume that scw_project is defined to check for its length but this may not always be the case., leading to a crash with a fairly obscure error. We should instead return a clearer error like scw_project is not defined, please add it to your Scaleway config or via the provider settings.

Problematic code here:

serverless-scaleway-functions/shared/validate.js

Line 66 in f430907

this.provider.getScwProject().length !== 36