Stop writing an empty environmentVariables to actor.json #1566

apify init writes "environmentVariables": {} into .actor/actor.json, and so does apify create for a template without an actor.json. On apify push, the empty object is truthy, so the CLI sends envVars: [] and deletes every env var set in Apify Console. This is the most common way Console values get wiped, and the fix is safe to ship on its own.

Scope

• Remove environmentVariables from EMPTY_LOCAL_CONFIG (src/lib/consts.ts).
• In apify push, treat an empty environmentVariables object as absent, so existing projects stop wiping the list (src/commands/actors/push.ts).
• Copy EMPTY_LOCAL_CONFIG in apify create instead of mutating the shared object (src/commands/create.ts).

Done when

• apify init followed by apify push to an existing Actor leaves the Actor's env vars untouched. An API test covers it.
• A push with "environmentVariables": {} sends no envVars.