Node Deployment Lesson: Removed Fly.io References

[Amiriel01]

Because

• Removed Fly.io references because it is no longer a free resource.

This PR

• Removed Fly.io reference in paragraph
• Removed Fly.io section in hosting sites

Issue

• Related to #28491

Additional Information

• See issue for comment notes.

Pull Request Requirements

• [x] I have thoroughly read and understand [The Odin Project curriculum contributing guide]
• [x] The title of this PR follows the location of change: brief description of change format, e.g. Intro to HTML and CSS lesson: Fix link text
• [x] The Because section summarizes the reason for this PR
• [x] The This PR section has a bullet point list describing the changes in this PR
• [x] If this PR addresses an open issue, it is linked in the Issue section
• [x] If any lesson files are included in this PR, they have been previewed with the Markdown preview tool to ensure it is formatted correctly
• [x] If any lesson files are included in this PR, they follow the Layout Style Guide