Browser viewport size becomes 14x14 when form minimized

### Is there an existing issue for this?

- [x] I have searched both open/closed issues, no issue already exists.

### CefSharp Version

138.0.170

### Operating System

Windows 11

### Architecture

x64

### .Net Version

.Net 4.7.2

### Implementation

WinForms

### Reproduction Steps

1. Open URL https://www.part987.com/en/standard/
2. Wait for website loading finished - it should look like normal desktop website
3. Minimize window

### Expected behavior

Website should remains unchanged

### Actual behavior

Website immediately changes to mobile version

### Regression?

_No response_

### Known Workarounds

This website tracks viewport size and redirects to mobile version as soon as width becomes small enough (about 400px and less). This is how we can check that viewport size has changed. I guess it becomes 1x1 or 0x0, but I can't confirm that.
It happens on window minimize, not on restore.

### Does this problem also occur in the CEF Sample Application

No

### Other information

Cefclient - works fine
CefSharp minimal application - problem exists

まず CefSharp の最小構成の WinForms アプリケーションで問題を再現し、その最小化時の動作を CEF サンプルアプリケーションおよび cefclient と比較します。WinForms ブラウザー統合がウィンドウの最小化と viewport の更新をどのように処理しているかを追跡します。完了条件は、フォームを最小化してもウェブサイトがモバイルレイアウトに変更されず、復元された viewport が正しいことです。

索引モデルが issue の本文から書いたものです。