feat: restore icon and context menu when Explorer restarts if necessary

[pzhlkj6612]

Hello! I'm going to fix #65.

To maintainers

To preserve the hard work from @brandon3343, I've being based on #39. Please don't forget to squash all commits into one before merging.

Test

The screen recordings for comparison:

Original version (973525c)	Fixed version
leanflutter-tray_manager-windows-taskbar-awareness-original.mp4	leanflutter-tray_manager-windows-taskbar-awareness-fixed.mp4

My test steps:

1. Open our example app and click "setContextMenu".
2. Click "popUpContextMenu" and click an item.
3. Set an icon and click it to show the menu, then click an item.
4. Click "popUpContextMenu" and click an item.
5. Restart Windows Explorer (e.g., by running powershell -command "gps explorer | spps"), then check system tray.
6. Click "popUpContextMenu" and click an item.
7. Click the icon to show the menu, then click an item.
8. Set an icon and click it to show the menu, then click an item.
9. Click "popUpContextMenu" and click an item.
10. Destroy the icon and set an icon, then click the icon to show the menu and click an item.
11. Click "popUpContextMenu" and click an item.
12. Destroy the icon.
13. Click "popUpContextMenu" and click an item.
14. Restart Windows Explorer, then check system tray.
15. Click "popUpContextMenu" and click an item.

The environment:

• OS: Windows 10 (10.0.15063); also tested on Windows 10 (10.0.19045.4780) and Windows 11 (10.0.22631.4317)
• Recorder: FastStone Capture 11.0

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[pzhlkj6612]

Sorry for being confusing. The title of this PR and the message of the key commit has been corrected:

- feat: restore icon and context menu when Explorer restarts if possible
+ feat: restore icon and context menu when Explorer restarts if necessary

We should NOT take care of possibility, but necessity.

[lijy91]

LGTM