Remove Ruby 2.7 specific lockfile step from workflow

The Ruby 2.7 lockfiles have different gem versions that are causing
test failures. Revert to using the standard lockfiles like main does.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

.github/workflows/ruby.yml

@@ -110,9 +110,6 @@ jobs:
         ruby-version: ${{ matrix.ruby }}
     - run: bundle config set --local path 'test/dummy/vendor/bundle'
     - run: ./test/bin/create-fake-js-package-managers ${{ matrix.js_package_manager.installer }}
-    - name: Use Ruby 2.7 specific lockfile
-      if: matrix.ruby == '2.7'
-      run: cp gemfiles/${{ matrix.gemfile }}.gemfile.ruby27.lock gemfiles/${{ matrix.gemfile }}.gemfile.lock
     - name: Save dummy app ruby gems to cache
       uses: actions/cache@v3
       with: