chore: Run prettier on CI (#5241)

* Add test:format to CI scripts, add prettier-plugin-svelte

* Run prettier

* Use prettier v4 alpha

* Mark test:format as root script

* Try bumping node version

Author: lachlancollins

.github/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
         with:
           version: 8
       - name: Setup Node
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
           node-version-file: .nvmrc
           cache: pnpm

.github/workflows/pr.yml

@@ -25,7 +25,7 @@ jobs:
         with:
           version: 8
       - name: Setup Node
-        uses: actions/setup-node@v3
+        uses: actions/setup-node@v4
         with:
           node-version-file: .nvmrc
           cache: pnpm