chore(ci): only install chrome when needed in unit test workflow (#5599)

* chore(ci): only install chrome when needed

let fast failures fail faster

* chore(ci): avoid rebuilding lwc when installing chromedriver

* chore(ci): use setup-chrome@v2

* Apply suggestion from @wjhsf

Author: wjhsf

.github/workflows/unit.yml

@@ -18,36 +18,22 @@ on:
 
 env:
     PUPPETEER_SKIP_DOWNLOAD: 'true' # only needed for @best/runner-local, unused here
+    CHROME_VERSION: 130
 
 jobs:
     run-unit-tests:
         runs-on: ubuntu-22.04
         steps:
             - name: Checkout repository
               uses: actions/checkout@v4
-
             - name: Setup Node
               uses: actions/setup-node@v4
               with:
                   node-version: '20.19.4'
                   cache: 'yarn'
-
-            # Needed for perf smoke tests, matches the chromedriver version installed by tachometer (https://github.com/google/tachometer/blob/main/README.md#on-demand-dependencies)
-            # chrome-version documentation can be found here: https://github.com/browser-actions/setup-chrome?tab=readme-ov-file#usage
-            - name: Setup chrome
-              uses: browser-actions/setup-chrome@v1
-              with:
-                  chrome-version: 130
-              id: setup-chrome
-
             - name: Install dependencies
               run: yarn install --frozen-lockfile
 
-            # Pin chromedriver to the same version as Chrome above, so Tachometer uses this version.
-            # See: https://github.com/google/tachometer#on-demand-dependencies
-            - name: Install chromedriver
-              run: yarn add -W chromedriver@^130
-
             - name: Check package.json integrity
               run: node ./scripts/tasks/check-and-rewrite-package-json.js --test
             - name: Check licenses are up to date
@@ -73,8 +59,26 @@ jobs:
               with:
                   name: test-coverage-report
                   path: coverage/
+
+            # Needed for perf smoke tests, matches the chromedriver version installed by tachometer (https://github.com/google/tachometer/blob/main/README.md#on-demand-dependencies)
+            # chrome-version documentation can be found here: https://github.com/browser-actions/setup-chrome?tab=readme-ov-file#usage
+            - name: Setup chrome
+              uses: browser-actions/setup-chrome@v2
+              with:
+                  chrome-version: ${{ env.CHROME_VERSION }}
+              id: setup-chrome
+
+            # Pin chromedriver to the same version as Chrome above, so Tachometer uses this version.
+            # See: https://github.com/google/tachometer#on-demand-dependencies
+            - name: Install chromedriver
+              run: yarn add -W chromedriver@^${{ env.CHROME_VERSION }} --ignore-scripts
+
             - name: Run benchmark smoke tests
-              run: CHROME_BINARY=${{ steps.setup-chrome.outputs.chrome-path }} BENCHMARK_SMOKE_TEST=1 yarn test:performance
+              run: yarn test:performance
+              env:
+                  BENCHMARK_SMOKE_TEST: 1
+                  CHROME_BINARY: ${{ steps.setup-chrome.outputs.chrome-path }}
+
             - name: Add step summary
               # 1. Remove leading/trailing "border" lines from output
               # 2. Wrap file names in backticks