ci: Move size check reruns into a local action

.github/workflows/size-check.yml

@@ -16,18 +16,21 @@ concurrency:
 jobs:
   rerun:
     if: github.event.label.name == 'Accept Bundlesize Increase'
-    runs-on: ubuntu-24.04
+    runs-on: namespace-profile-sentry-javascript;overrides.cache-tag=sentry-javascript
     timeout-minutes: 60
     steps:
-      - name: Check out base commit
+      - name: Check out workflow commit
         uses: actions/checkout@v7
         with:
-          ref: ${{ github.event.pull_request.base.sha }}
+          ref: ${{ github.workflow_sha }}
           persist-credentials: false
-      - uses: actions/github-script@v9
+      - name: Set up Node
+        uses: actions/setup-node@v7
         with:
-          script: |
-            const { default: run } = await import(
-              `${process.env.GITHUB_WORKSPACE}/scripts/rerun-size-check.mjs`
-            );
-            await run({ github, context, core });
+          node-version-file: 'package.json'
+      - name: Install dependencies
+        uses: ./.github/actions/install-dependencies
+      - name: Rerun Size Check
+        uses: ./dev-packages/size-limit-gh-action/rerun
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}

dev-packages/size-limit-gh-action/rerun/action.yml

@@ -0,0 +1,11 @@
+name: Rerun Size Check
+description: Rerun Size Check after the bundle size approval label changes
+
+inputs:
+  github_token:
+    description: Token with permission to read pull requests and rerun workflow jobs
+    required: true
+
+runs:
+  using: node24
+  main: index.mjs

scripts/rerun-size-check.mjs → dev-packages/size-limit-gh-action/rerun/index.mjs

@@ -1,4 +1,8 @@
-export default async function rerunSizeCheck({ github, context, core }) {
+import * as core from '@actions/core';
+import { context, getOctokit } from '@actions/github';
+
+async function rerunSizeCheck() {
+  const github = getOctokit(core.getInput('github_token', { required: true }));
   const pr = context.payload.pull_request;
 
   const runs = await github.paginate(github.rest.actions.listWorkflowRuns, {
@@ -58,3 +62,5 @@ export default async function rerunSizeCheck({ github, context, core }) {
     job_id: job.id,
   });
 }
+
+await rerunSizeCheck().catch(error => core.setFailed(error.message));