chore: revert native tests to yarn workspace

prepare:ios/android and test:ios/android are not turbo tasks.
These scripts don't use root-level binaries so yarn workspace works.

Author: soberm

.github/workflows/callable-native-unit-tests.yml

@@ -25,12 +25,12 @@ jobs:
         env:
           TEST_PACKAGE: ${{ matrix.package.name }}
         run: |
-          yarn turbo run prepare:ios --filter=$TEST_PACKAGE
-          yarn turbo run test:ios --filter=$TEST_PACKAGE
+          yarn workspace $TEST_PACKAGE prepare:ios
+          yarn workspace $TEST_PACKAGE test:ios
       - name: Run Android Tests
         working-directory: ./amplify-js
         env:
           TEST_PACKAGE: ${{ matrix.package.name }}
         run: |
-          yarn turbo run prepare:android --filter=$TEST_PACKAGE
-          yarn turbo run test:android --filter=$TEST_PACKAGE
+          yarn workspace $TEST_PACKAGE prepare:android
+          yarn workspace $TEST_PACKAGE test:android