Move get-ref-from-pr to actions repo for reuse

Author: dhaidashenko

.github/scripts/get-refs-from-pr-body.js

@@ -21,15 +21,23 @@ jobs:
       solana-ref: ${{ steps.set-git-refs.outputs.solana-ref }}
       starknet-ref: ${{ steps.set-git-refs.outputs.starknet-ref }}
     steps:
-      - uses: actions/checkout@v4
+      # Checkout the shared scripts from the smartcontractkit/.github repo.
+      - name: Checkout shared .github scripts
+        uses: actions/checkout@v4
         with:
+          repository: smartcontractkit/.github
+          # TODO: pin to a commit SHA once the get-refs-from-pr-body.js PR is merged into smartcontractkit/.github.
+          ref: feature/get-ref-from-pr-body
           persist-credentials: false
+          sparse-checkout: tools/scripts/get-refs-from-pr-body.js
+          sparse-checkout-cone-mode: false
+          path: shared-github
       - name: Get refs from PR body
         id: set-git-refs
         uses: actions/github-script@v7
         with:
           script: |
-            const script = require('./.github/scripts/get-refs-from-pr-body.js')
+            const script = require(`${process.env.GITHUB_WORKSPACE}/shared-github/tools/scripts/get-refs-from-pr-body.js`)
             await script({ github, context, core })
 
   build-chainlink: