Add unprefixed mask support in Chromium

All of the other `mask-` properties were unprefixed at the same time, only this one was left unmodified. I think this was missed in the course of running automatic updates for Chrome 120. See: mdn#21148 (comment)

css/properties/mask.json

@@ -7,13 +7,17 @@
           "spec_url": "https://drafts.fxtf.org/css-masking/#the-mask",
           "support": {
             "chrome": [
+              {
+                "version_added": "120"
+              },
               {
                 "prefix": "-webkit-",
                 "version_added": "1",
                 "notes": "The prefixed property can be used with SVG and HTML with a slightly different syntax, which allows setting the non-standard <a href='https://developer.mozilla.org/docs/Web/CSS/-webkit-mask-attachment'><code>-webkit-mask-attachment</code></a> property."
               },
               {
                 "version_added": "1",
+                "version_removed": "120",
                 "partial_implementation": true,
                 "notes": "While the property is recognized, values applied to it don't have any effect."
               }