Env vars duplicated for Netlify Github Action

[sw360cab]

When running Netlify Github Action, the following env vars:

• MEILISEARCH_URL
• MEILISEARCH_INDEX_UID
• MEILISEARCH_API_KEY

are reported twice:

• in netlify.toml, which is the reference file for Netlify deploys, in the [context.production.environment] section
• in .github/workflows/netlify.yml, which performs the build (pure build in yarn) using the env vars and then deploys to Netlify (referring to netlify.toml)

The variables should be centralized in a single place, however is not clear:

• why the build step in the Github Action is not performed using the steps described in the build section of netlify.toml
• if [context.production.environment] section is the right place to define these env vars, or it is useless (IMHO) to have them here