windows: Refactor clipboard implementation (#14347)

This PR provides a similar implementation to the macOS clipboard
implementation, adds support for metadata and includes tests.

Release Notes:

- N/A

crates/gpui/src/platform.rs

@@ -406,6 +406,8 @@ pub(crate) trait PlatformTextSystem: Send + Sync {
         raster_bounds: Bounds<DevicePixels>,
     ) -> Result<(Size<DevicePixels>, Vec<u8>)>;
     fn layout_line(&self, text: &str, font_size: Pixels, runs: &[FontRun]) -> LineLayout;
+    #[cfg(target_os = "windows")]
+    fn destroy(&self);
 }
 
 #[derive(PartialEq, Eq, Hash, Clone)]