Remove infinite version existence check

[carlydf]

What was changed

What it says in the title.
Replaced with Version Status == NotRegistered condition in planning phase.
Also reorganized test helper functions, ensured that Deployments created by test helpers can be found by the controller, and added a failed and successful Gate workflow test.

Why?

Because checking for version existence in execplan.go breaks the abstraction of only reading server status in gen status. And we have the information to not do another describe, so we should use it.

Changes to test files are so that helper functions and test functions are separated and easier to read and work on.

Checklist

1. Closes Remove infinite loop from Version Registration check #57

2. How was this tested:
   New tests specific to Gate workflows ensure that we are not starting those workflows on a non-existent version, and old tests also show that SetCurrent and SetRamping calls are not erroring due to nonexistent version.

3. Any docs updates needed?
   no

[Copilot]

Pull Request Overview

This PR removes the infinite version existence check that was performed before registering versions with Temporal, replacing it with a condition to check if the version status is NotRegistered in the planning phase. This improves abstraction by avoiding redundant server calls when status information is already available.

Key changes:

• Replace version existence checks with NotRegistered status conditions in planning phase
• Reorganize test helper functions into separate files for better maintainability
• Add new Gate workflow tests for both successful and failed scenarios

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
internal/controller/util.go	Remove awaitVersionRegistration and related functions
internal/controller/execplan.go	Remove version existence checks before registering versions
internal/planner/planner.go	Add NotRegistered status checks to prevent actions on unregistered versions
internal/k8s/deployments.go	Add NewDeploymentWithControllerRef helper function
internal/controller/genplan.go	Simplify deployment creation using new helper
internal/testhelpers/workers.go	Move worker functions to testhelpers package and add Gate workflow types
internal/tests/internal/deployment_controller.go	Extract deployment controller functions from env_helpers
internal/tests/internal/env_helpers.go	Remove deployment functions, add testEnv struct
internal/tests/internal/integration_test.go	Add Gate workflow tests and reorganize test structure
internal/tests/internal/validation_helpers.go	Add nil check and fix error message terminology
internal/testhelpers/test_builder.go	Add Gate configuration and wait time support