Update to use actions/checkout@v4 to avoid Node 16 usage warnings

[shayancanonical]

Issue

1. We have some commented out CI steps that are not being used
2. We are using actions/checkout@v3 which is causing the following warning in test runs:

Node.js 16 actions are deprecated. Please update the following actions to use Node.js 20: actions/checkout@v3, canonical/charming-actions/[email protected]. For more information see: https://github.blog/changelog/2023-09-22-github-actions-transitioning-from-node-16-to-node-20/.

Solution

1. Remove commented steps in CI
2. Update to use actions/checkout@v4