Fix codegen workflow

Author: robin-aws

.github/workflows/ci_codegen.yml

@@ -51,15 +51,6 @@ jobs:
       - name: Create temporary global.json
         run: echo '{"sdk":{"rollForward":"latestFeature","version":"6.0.0"}}' > ./global.json
 
-      - name: Setup Java 17 for codegen
-        uses: actions/setup-java@v3
-        with:
-          distribution: "corretto"
-          java-version: "17"
-
-      - name: Install Smithy-Dafny codegen dependencies
-        uses: ./.github/actions/install_smithy_dafny_codegen_dependencies
-
       - uses: ./.github/actions/polymorph_codegen
         with:
           dafny: ${{ inputs.dafny }}