Auto merge of #24280 - ferjm:webm, r=jdm

Allow playing video/webm on Windows

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

This makes video/webm play on non-UWP Windows. I couldn't find the equivalent gstmatroska.dll on our GStreamer binaries for UWP.

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components/servo/lib.rs

@@ -194,6 +194,7 @@ mod media_platform {
         ];
 
         let non_uwp_plugins = [
+            "gstmatroska.dll",
             "gstnice.dll",
             "gstogg.dll",
             "gstopengl.dll",