Resolve "Send deployment information in job API"

What does this MR do?

Extend BuildDetailEnity to include a new key deployment_status which has all the information about deployments.

What are the relevant issue numbers?

gitlab-org/gitlab-ce#50460

gitlab-org/gitlab-ce#50101

To Do

• Create issue for environment json schema

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides

Closes #50460 (closed)

app/serializers/build_details_entity.rb

@@ -7,6 +7,10 @@ class BuildDetailsEntity < JobEntity
   expose :runner, using: RunnerEntity
   expose :pipeline, using: PipelineEntity
 
+  expose :deployment_status do |build|
+    DeploymentStatusEntity.new(build, request: request)
+  end
+
   expose :metadata, using: BuildMetadataEntity
 
   expose :erased_by, if: -> (*) { build.erased? }, using: UserEntity