[Testing][!Assertation] Allow choosing IF and WHICH Assertation Package, we want to use!

[DevTKSS]

What would you like to be added:

Provide a choice, when we are opting into adding Test Projects to our Uno Solution Apps:

1. Do we want an additional Assertation Package AT ALL ?

   If we not want any, please just provide a test project with the general choosen testing Framework like NUnit / xUnit with the current sample content adjusted to the base Test Framework syntax (for this with xUnit, I added a diff as proposal to change/add onto [ProjectTemplates/SolutionTemplates][Testing] Add xUnit Testing Project to options for Wizard to include in new Uno Apps #1258 )

2. Add a checkbox based option in each of the Test Project boxes we now have in the VS2022 Wizard, that allows us to also decide differently per Test Project option

3. Provide a Choice of at least two different Assertation Packages, like:

• the current FluentAssertion

  [!IMPORTANT]
  Add a Remark to this option, that will tell us that for the >= v8 of this, this may requires a payed License, so we would pay special Attention to maybe fix the version by using Version="[7.2.0]" on the Directory.Packages.props file!

• alternatives like:

  • Shouldly
  • AwesomeAssertions (which is a Community Fork of the < v8 of FluentAssertions)

Why is this needed:

For which Platform:

• iOS
• Android
• WebAssembly
• WebAssembly renders for Xamarin.Forms
• Windows
• Build tasks
• Testing

Anything else we need to know?

Please evaluate the Importance for us Users of the Templates to the FluentAssertions Package, so we will know of the payed licensing Detail and react properly if required.
I do absolutly know without doubt, that Uno does not provide those Templates with those critical Version numbers, so just from the Template, thats no Issue, but I do also think, that Uno has only our best and success with the sdk and templates in mind, so I hoping, that this "Small" Remark about this, (for us very important to know of) is a considerable effort to implement, even if it's an extenal Provider we are using.

Nobody is perfect! And in the Real Life, there is sometimes stressfull times, coming from duedates or a boss sitting in our Neck putting even more Pressure on us, so this little but Important Details could help us greatly, to notice this!

[Takoooooo]

Thanks, this one totally makes sense for me! I would probably suggest adding 3 options for the Assertion library - None, Shouldly, FluentAssertions. Cc @jeromelaban @MartinZikmund so we can come to some decision