Remove defunct deploy-demo make action

[nrichers]

Internal Notes for Reviewers

This PR removes one of those 'we should fix this some day' annoyances that I've spent more time explaining in the last week than it would take to fix. This PR fixes THE LAST PIECE in the puzzle.

Before
We had an extra docs site in the root of the s3://docs-ci-cd-demo bucket that goes back to the very early days of Andres and I experimenting with docs deployment. This site serves no purpose, is not current, and is not used — other than we need in index.html in the root of origin/ for the PR previews to work.

You could deploy this site with make deploy-demo.

After
This site has now been deleted, replaced with an index.html that redirects to https://docs-staging.validmind.ai/ if you try to access the root of origin/. Eventually, we might want to list all the PR previews but for now, not having a stale, defunct docs site kicking around that I have to explain is an improvement.

The make deploy-demo is removed in this PR, preventing accidental redeployment of the site.

External Release Notes

[github-actions]

PR Summary

This pull request removes the deploy-demo target from the Makefile. The deploy-demo target was responsible for deploying the documentation demo site to the S3 bucket s3://docs-ci-cd-demo/site/. The removal includes both the .PHONY declaration and the actual target implementation. The deploy-demo-branch target remains intact, allowing deployment of documentation demo sites to branch-specific directories within the same S3 bucket.

The change simplifies the Makefile by eliminating a deployment option that may no longer be necessary or used, potentially reducing maintenance overhead and the risk of deploying to an incorrect environment.

Test Suggestions

• Verify that the Makefile executes without errors after the removal of the 'deploy-demo' target.
• Ensure that the 'deploy-demo-branch' target still functions correctly and deploys to the expected S3 path.
• Check for any documentation or scripts that reference the removed 'deploy-demo' target and update them accordingly.
• Test the deployment process to ensure no unintended side effects occur due to the removal of the 'deploy-demo' target.

[github-actions]

A PR preview is available: Preview URL

[github-actions]

A PR preview is available: Preview URL

[validbeck]

Let's gooo 🎉