Add copy button to resources in Typography sample page

[AndrewKeepCoding]

What would you like to be added:

A copy button for each resource in the Typography sample page.

Why is this needed:

It makes easier to copy resource names to clipboard.

For which Platform:

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

Anything else we need to know?

The WinUI Gallery's Typography sample page has copy buttons.

[Xiaoy312]

for reference: // win+r: winui3gallery://item/Typography

button copies the style key