Add warning for Fluent-only icons not available on Windows 10

[Zakariathr22]

Description

Added a warning to indicate that some icons may not be available by default on Windows 10, especially those only included in the Segoe Fluent Icons set used by Windows 11. Main changes are:

• Added IsSegoeFluentOnly property to both the IconDataSchema and IconData class.
• Marked Fluent-only icons in the JSON data.
• Displayed a warning icon and message on the Iconography page for Fluent-only icons.

Motivation and Context

• This change helps clarify icon availability across different Windows versions.
• Closes Icons don't warn about Win10 not supported #1557.

How Has This Been Tested?

Tested by manually setting the font to Segoe MDL2 Assets to simulate the default icon set on Windows 10 and verifying which icons fail to appear.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

[niels9001]

Amazing work as always! Added a few suggestions

Would love to get @dotMorten 's feedback too

[niels9001]

/azp run