Remove redundant build JS steps

Author: danyeaw

.github/workflows/js.yml

@@ -73,7 +73,6 @@ jobs:
       - name: Install dependencies
         run: |
           pip install --upgrade pip
-          npm run build
           npm install -g casperjs@1.1.4 phantomjs-prebuilt@2.1.16
           pip install .[test]
 

.github/workflows/playwright.yml

@@ -33,10 +33,6 @@ jobs:
       with:
         node-version: '16.x'
 
-    - name: Install and build JS
-      run: |
-        npm run build
-
     - name: Install Python dependencies
       run: |
         python tools/install_pydeps.py