Fix serverless environment spec for smoke tests deployment

Add environment_version to the serverless environment definition.
Databricks requires a spec with version for environment keys.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: caseydm

jobs/snapshot_full.yaml

@@ -317,6 +317,8 @@ resources:
             is_single_node: true
       environments:
         - environment_key: serverless
+          spec:
+            environment_version: "4"
       git_source:
         git_url: https://github.com/ourresearch/openalex-walden.git
         git_provider: gitHub