fix(platform-server): handle styles with extra ':'s correctly (#15189)

Previously, style values were parsed with a regex that split on /:+/.

This causes errors for CSS such as

div {
  background-url: url(http://server.com/img.png);
}

since the regex would split the background-url line into 3 values instead of 2.

Now, the : character is detected with indexOf, avoiding this error.

A test was added to verify the behavior is correct.

packages/platform-server/src/parse5_adapter.ts

@@ -427,8 +427,12 @@ export class Parse5DomAdapter extends DomAdapter {
       const styleList = styleAttrValue.split(/;+/g);
       for (let i = 0; i < styleList.length; i++) {
         if (styleList[i].length > 0) {
-          const elems = styleList[i].split(/:+/g);
-          (styleMap as any)[elems[0].trim()] = elems[1].trim();
+          const style = styleList[i] as string;
+          const colon = style.indexOf(':');
+          if (colon === -1) {
+            throw new Error(`Invalid CSS style: ${style}`);
+          }
+          (styleMap as any)[style.substr(0, colon).trim()] = style.substr(colon + 1).trim();
         }
       }
     }