docs: Copilot privacy concerns

[MarcinVaadin]

Added Privacy Concerns section with more detailed information about what is being sent and how to opt out.

[github-actions]

AI Language Review

The review reveals that the main addition to the document is the "Privacy" section, outlining how Copilot handles data sharing and privacy. Here are a few suggested improvements for this new section:

1. Clarity:

   • In the "Shared data" column, instead of "Source code related to given view, depending on operation," consider specifying what "given view" refers to for more clarity.
   • In "Copilot error" row, specify what constitutes "Telemetry" and ensure it's clear what data is included in "Vaadin dependencies versions" to avoid ambiguity.

2. Consistency:

   • The opt-out instructions should consistently guide users to the Vaadin settings or system properties sections. If one method is preferable, highlight it.

3. Formatting:

   • Ensure that system properties (vaadin.devmode.usageStatistics.enabled) are formatted consistently throughout the text and with inline code syntax for easier reading.

These changes should improve the clarity and consistency of the new section's content.

[emarc]

Looks goo, I suggest the following adjustments:

1. Name the section just "Privacy" (drop "concerns")
2. "User is asked before first operation if AI usage is allowed." -> "User asked for permission before operation. This can be changed via Settings > AI Usage"
3. "Command Window prompt submitted": add "User asked for permission before operation (same as above.)"
4. "User Activity" -> "Copilot usage" (not super good, but works well with the next one)
5. "Copilot error happened" -> "Copilot error"

[emarc]

"Command Window prompt submitted": add "User asked for permission before operation (same as above.)"

Now the part about settings about settings on vaadin.com is completely dropped?