fix(tray): support Unicode for NotifyIcon.TooltipText

[chucker]

Explicitly use the Unicode (wide) variant of Shell_NotifyIcon.

Pull request type

Please check the type of change your PR introduces:

• Update
• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes

What is the current behavior?

Issue Number: fixes #1705

Other information

I tried to migrate this to [LibraryImport] and CsWin32, but both of those seemed to be too much of a rabbit hole.

[BlyZeDev]

I implemented a NotifyIcon using LibraryImport. Might be of good use here: https://github.com/BlyZeDev/DotTray

[chucker]

I implemented a NotifyIcon using LibraryImport. Might be of good use here: https://github.com/BlyZeDev/DotTray

Thanks. I tried to use LibraryImport or CsWin32, but it seemed non-trivial to make them not clash with PolySharp.