fix: duplicate textContent for style element cause incremental style mutation invalid (#1417)

fix style element corner case
 - historically we have recorded duplicated css content in certain cases (demonstrated by the attached replayer test). This fix ensures that the replayer doesn't doubly add the content, which can cause problems when further mutations occur
---------
Review and further tests contributed by: Eoghan Murray <eoghan@getthere.ie>

packages/rrweb-snapshot/src/rebuild.ts

@@ -160,8 +160,9 @@ function buildNode(
           value = adaptCssForReplay(value, cache);
         }
         if ((isTextarea || isRemoteOrDynamicCss) && typeof value === 'string') {
-          node.appendChild(doc.createTextNode(value));
           // https://github.com/rrweb-io/rrweb/issues/112
+          // https://github.com/rrweb-io/rrweb/pull/1351
+          node.appendChild(doc.createTextNode(value));
           n.childNodes = []; // value overrides childNodes
           continue;
         }