feat(amplify_foundation_dart): Add dart2wasm_args to build.yaml (#6764)

Configure build_web_compilers entrypoint builder with dart2wasm_args mirroring the existing dart2js_args for release builds.

Author: Jonas Greifenhain

packages/amplify_foundation/amplify_foundation_dart/build.yaml

@@ -9,3 +9,6 @@ targets:
           dart2js_args:
             - --define=dart.vm.product=true
             - --enable-asserts
+          dart2wasm_args:
+            - --define=dart.vm.product=true
+            - --enable-asserts