Fix case where we have empty mypy folder array in ci workflow (apache#38282)

When no python files change we have empty mypy-folders array.
We have to skip the whole strategy matrix in this case.

Author: potiuk

.github/workflows/mypy.yml

@@ -50,6 +50,7 @@ jobs:
       fail-fast: false
       matrix:
         mypy-folder: ${{fromJson(inputs.mypy-folders)}}
+    if: inputs.needs-mypy == 'true'
     env:
       RUNS_ON: "${{inputs.runs-on}}"
       PYTHON_MAJOR_MINOR_VERSION: "${{inputs.default-python-version}}"
@@ -59,19 +60,15 @@ jobs:
       - name: "Cleanup repo"
         shell: bash
         run: docker run -v "${GITHUB_WORKSPACE}:/workspace" -u 0:0 bash -c "rm -rf /workspace/*"
-        if: inputs.needs-mypy == 'true'
       - name: "Checkout ${{ github.ref }} ( ${{ github.sha }} )"
         uses: actions/checkout@v4
         with:
           persist-credentials: false
-        if: inputs.needs-mypy == 'true'
       - name: Cleanup docker
         uses: ./.github/actions/cleanup-docker
-        if: inputs.needs-mypy == 'true'
       - name: "Prepare breeze & CI image: ${{ inputs.default-python-version }}:${{ inputs.image-tag }}"
         uses: ./.github/actions/prepare_breeze_and_image
         id: breeze
-        if: inputs.needs-mypy == 'true'
       - name: "MyPy checks for ${{ matrix.mypy-folder }}"
         run: |
           pip install pre-commit
@@ -83,4 +80,3 @@ jobs:
           DEFAULT_BRANCH: ${{ inputs.default-branch }}
           RUFF_FORMAT: "github"
           INCLUDE_MYPY_VOLUME: "false"
-        if: inputs.needs-mypy == 'true'