Changes testing to use the new setup-blender GHA

[BradyAJohnston]

Changes the test to use the new setup-blender GHA that I created.

Doesn't do any fancy scraping of versions, just downloads and installs the specified version numbers, up to the user to provide.

Now a much smaller .yml file is required:

name: Run Tests

on: 
    push:
      branches: ["main"]
    pull_request:
      branches: ["*"]
    
jobs:
    build:
        runs-on: ${{ matrix.os }}
        strategy:
            max-parallel: 4
            fail-fast: false
            matrix:
              version: ["4.2", "4.3"]
              os: [macos-14, "ubuntu-latest", "windows-latest"]
        steps:
            - uses: actions/checkout@v4
            - name: Install Blender
              uses: bradyajohnston/setup-blender@v1
              with:
                version: ${{ matrix.version }}
            - name: Run tests in Blender
              run: blender --version