chore(ci): Remove redundant build step for design system

The build step for the design system was recently added to the `prepare` script, so it's automatically built after dependencies are installed.

.github/workflows/ci.yml

@@ -46,10 +46,6 @@ jobs:
       - name: Lint
         run: pnpm lint
 
-      - name: Build design system
-        run: pnpm build
-        working-directory: packages/design-system
-
       - name: Run Tests
         run: pnpm test
 
@@ -73,10 +69,6 @@ jobs:
       - name: Install Dependencies
         run: pnpm install --no-lockfile
 
-      - name: Build design system
-        run: pnpm build
-        working-directory: packages/design-system
-
       - name: Run Tests
         run: pnpm test
 
@@ -124,10 +116,6 @@ jobs:
       - name: Install Dependencies
         run: pnpm install --frozen-lockfile
 
-      - name: Build design system
-        run: pnpm build
-        working-directory: packages/design-system
-
       - name: Run Tests
         run: ./node_modules/.bin/ember try:one ${{ matrix.try-scenario }} --skip-cleanup
         working-directory: packages/ember-test-app