[AIAvatar] Newton Json dependency

[HJLeee]

I happen to come across AIAvatar impl and realize that it uses Newton Json as below.

TizenFX/src/Tizen.AIAvatar/Tizen.AIAvatar.csproj

Line 10 in 149fe2f

<PackageReference Include="Newtonsoft.Json" Version="11.0.2" />

This could create a version mismatch when app uses other version of newton json.
Also, System.Text.Json is known to be faster and take less memory.
Please fix the potential bug before it is released.

[github-actions]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days

[HJLeee]

It seems @huiyueun is no longer in charge of AIAvatar but @dongsug-song from the log.