Auto merge of #17739 - jdm:no-vendor-prefixed-errors, r=emilio

Suppress CSS parser errors for vendor-prefixed properties.

This matches the behaviour of Gecko's CSS parser.

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #17736
- [X] There are tests for these changes

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components/style/properties/gecko.mako.rs

@@ -2871,7 +2871,7 @@ fn static_assert() {
                         Gecko_AppendWillChange(&mut self.gecko, feature.0.as_ptr());
                     }
 
-                    if let Ok(prop_id) = PropertyId::parse(feature.0.to_string().into()) {
+                    if let Ok(prop_id) = PropertyId::parse(&feature.0.to_string()) {
                         match prop_id.as_shorthand() {
                             Ok(shorthand) => {
                                 for longhand in shorthand.longhands() {