don't use contentVisibility on Firefox (#4164)

src/view/com/util/List.web.tsx

@@ -504,6 +504,7 @@ export const List = memo(React.forwardRef(ListImpl)) as <ItemT>(
 
 // https://stackoverflow.com/questions/7944460/detect-safari-browser
 const isSafari = /^((?!chrome|android).)*safari/i.test(navigator.userAgent)
+const isFirefox = /firefox|fxios/i.test(navigator.userAgent)
 
 const styles = StyleSheet.create({
   sideBorders: {
@@ -518,7 +519,7 @@ const styles = StyleSheet.create({
   },
   row: {
     // @ts-ignore web only
-    contentVisibility: isSafari ? '' : 'auto', // Safari support for this is buggy.
+    contentVisibility: isSafari || isFirefox ? '' : 'auto', // Safari support for this is buggy.
   },
   minHeightViewport: {
     // @ts-ignore web only