Update Fluent UI 9 demo to latest SPFX and Fluent UI 9 (with overrides)

[techienickb]

• Bug fix?
• New sample?
• Related issues: fixes #X, partially #Y, mentioned in #Z
• Needs API permissions?
• Has other prerequisites? (E.g. requires a list, document library, etc.)

What's in this Pull Request?

Updated Fluent UI 9 demo to latest Fluent UI and SPFX. Overrides are currently needed for fluent ui 9 due to a webpack issue with SPFX and Fluent UI 9 using a later web-packable package.

Node Version

Node version used: 18

Checklist

• My pull request affects only ONE sample.
• My sample does not build with any warnings
• I have updated the README file.
• My README has at least one static high-resolution screenshot (i.e. not a GIF)
• My README contains complete setup instructions, including pre-requisites and permissions required

[hugoabernier]

Thank you for your sample @techienickb ! Looking forward to your next one!!!