chore: remove duplicated code and fix minor bugs

[dejanzele]

Pull Request Template

Description

Please include a summary of the changes and the related issue (if any). Describe your changes in detail to help reviewers understand your contribution.

• What is the purpose of this PR?
• Cleanup of duplicated logic and minor bugfixes
• What was changed?
• Nothing feature-wise
• Why was it changed?
• Improve stability and reusability
• Does this address any existing issues or enhancement requests?
• No

Fixes # (issue)

Type of change

Please select the type of change your PR introduces:

• [x] Bugfix
• [ ] Feature
• [ ] Code Style Update (formatting, renaming)
• [x] Refactor (code changes that do not fix a bug or add a feature)
• [ ] Documentation Update
• [ ] Other (please describe):

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions to reproduce these tests. List any relevant details for your test configuration.

• Test Configuration:

  • Kubernetes Version:
  • Helm Version:
  • OS:

• Test Steps:

  1. Step 1
  2. Step 2
  3. ...

Checklist:

• [ ] My code follows the style guidelines of this project.
• [ ] I have performed a self-review of my code.
• [ ] I have commented on my code, particularly in hard-to-understand areas.
• [ ] I have made corresponding changes to the documentation.
• [ ] My changes generate no new warnings.
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [ ] New and existing unit tests pass locally with my changes.
• [ ] Any dependent changes have been merged and published in downstream modules.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 59.68992% with 104 lines in your changes missing coverage. Please review.

Project coverage is 84.67%. Comparing base (d82cf81) to head (e249792). Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/controller/install/lookout_controller.go	45.94%	11 Missing and 9 partials :warning:
...ternal/controller/install/binoculars_controller.go	41.37%	9 Missing and 8 partials :warning:
internal/controller/install/executor_controller.go	42.85%	8 Missing and 8 partials :warning:
...nternal/controller/install/scheduler_controller.go	42.85%	6 Missing and 6 partials :warning:
...rnal/controller/install/armadaserver_controller.go	65.51%	6 Missing and 4 partials :warning:
internal/controller/install/common_helpers.go	85.93%	6 Missing and 3 partials :warning:
...controller/install/scheduleringester_controller.go	61.90%	4 Missing and 4 partials :warning:
...nal/controller/install/eventingester_controller.go	53.84%	3 Missing and 3 partials :warning:
...l/controller/install/lookoutingester_controller.go	62.50%	3 Missing and 3 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #326 +/- ## ========================================== + Coverage 84.30% 84.67% +0.36% ========================================== Files 15 15 Lines 3467 3327 -140 ========================================== - Hits 2923 2817 -106 + Misses 381 353 -28 + Partials 163 157 -6 ```

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