Draft: Support `!reference` tag in CI interpolation

What does this MR do and why?

Given:

spec:
  inputs:
    job_name:
      default: 'test'
---
test:
  script: echo
  rules:
    - if: $TEST_VAR

build:
  script: echo
  rules: !reference ["$[[inputs.job_name]]", "rules"]

Full configuration output:

---
test:
  script: echo
  rules:
  - if: "$TEST_VAR"
build:
  script: echo
  rules:
  - if: "$TEST_VAR"

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Before	After

How to set up and validate locally

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MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.

Related to #424481