Add Wasm builds to pull_request.yml

Author: MaxDesiatov

.github/workflows/pull_request.yml

@@ -20,6 +20,7 @@ jobs:
     uses: swiftlang/github-workflows/.github/workflows/swift_package_test.yml@main
     with:
       enable_cross_pr_testing: true
+      enable_wasm_sdk_build: true
   soundness:
     name: Soundness
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main