Fix bug causing find widget to appear in extensions search box

Fix title rendering issues (ellipsis, clipping)

* Add WebviewPanel.iconPath

Allows webviews to provide icons used in UI. Adds a new `WebviewPanel.iconPath` property for this.

Replaces the static contribution approach from #49657

Fixes #48864

* Fix doc

* Move icon into mainthreadwebview

* Cleaning up implementation

* Cleaning up implementation

* zh-hans and zh-hant are invalid locales

* Allow more than 1 result in the gallery query

Update badge in panel title

Fixes #54949

Fixes #53372 

as part of the localization effort @agriffard noticed that an english string was incorrect - fixed here

fixes #52399

fixes #52401