Closes: https://github.com/fleetdm/fleet/issues/47653
Changes:
- Updated the contact page to only display the "Talk to us" form if a
user visits it with a `?talkToUs` query string.
- Updated all "Get a demo" buttons to go to `/contact?talkToUs`
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## Summary by CodeRabbit
* **New Features**
* Added a dedicated “Talk to us” contact experience.
* Updated “Get a demo,” “Talk to sales,” and “Talk to an engineer” links
across the site to open the appropriate contact form directly.
* **Bug Fixes**
* Improved contact form selection so the requested form displays
consistently across supported pages.
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