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

 # frozen_string_literal: true
 
 class BuildDetailsEntity < JobEntity
+  include EnvironmentHelper
+  include RequestAwareEntity
+  include CiStatusHelper
+
   expose :coverage, :erased_at, :duration
   expose :tag_list, as: :tags
   expose :user, using: UserEntity
   expose :runner, using: RunnerEntity
   expose :pipeline, using: PipelineEntity
 
+  expose :deployment_status, if: -> (*) { build.has_environment? } do
+    expose :deployment_status, as: :status
+
+    expose :icon do |build|
+      ci_label_for_status(build.status)
+    end
+
+    expose :persisted_environment, as: :environment, with: EnvironmentEntity
+  end
+
   expose :metadata, using: BuildMetadataEntity
 
   expose :artifact, if: -> (*) { can?(current_user, :read_build, build) } do