Validate that no static redirect routes are present in public/__redirects after any dynamic rule has been declared to avoid over shadowing

Summary

The order of application of redirect rules matters. From the documentation:
https://developers.cloudflare.com/pages/configuration/redirects/#per-file:

• The order of your redirects matter. If there are multiple redirects for the same source path, the top-most redirect is applied.
• Static redirects should appear before dynamic redirects.

This change helps to enforce these points.

Output on issue

When a static route is found after any dynamic route has been declared the output is similar to the following:

✘ Found static redirect after dynamic redirect:
    /zoo/

Detected errors:
- 1 static redirect(s) after dynamic redirect(s)

and the bin/validate-redirects.ts will return a non-zero (error) code

Documentation checklist

This adds an additional validation to the rules listed in public/__redirects that should be triggered ahead of merging