experimental: Content mode icon and a new preview mode icon (#4473)

## Description

1. What is this PR about (link the issue and add a short description)

## Steps for reproduction

1. click button
2. expect xyz

## Code Review

- [ ] hi @kof, I need you to do
  - conceptual review (architecture, feature-correctness)
  - detailed review (read every line)
  - test it on preview

## Before requesting a review

- [ ] made a self-review
- [ ] added inline comments where things may be not obvious (the "why",
not "what")

## Before merging

- [ ] tested locally and on preview environment (preview dev login:
0000)
- [ ] updated [test
cases](https://github.com/webstudio-is/webstudio/blob/main/apps/builder/docs/test-cases.md)
document
- [ ] added tests
- [ ] if any new env variables are added, added them to `.env` file

apps/builder/app/builder/features/topbar/builder-mode.tsx

@@ -1,5 +1,9 @@
 import { useStore } from "@nanostores/react";
-import { EditIcon, PaintBrushIcon, PlayIcon } from "@webstudio-is/icons";
+import {
+  NotebookAndPenIcon,
+  PaintBrushIcon,
+  PlayIcon,
+} from "@webstudio-is/icons";
 import {
   Box,
   DropdownMenuItemRightSlot,
@@ -56,7 +60,7 @@ export const BuilderModeDropDown = () => {
       enabled: isDesignModeAllowed,
     },
     content: {
-      icon: <EditIcon />,
+      icon: <NotebookAndPenIcon />,
       description: "Modify the page content",
       title: "Build",
       shortcut: ["cmd", "shift", "b"],