Split IssueService/RawIssueService so renderer proc consumers have a simpler interface to launch the issue reporter

- Custom view service to get tree item viewer
- Custom view service to register the data provider

Cancelling opening a folder from a multi-root unsaved workspace corrupts the current worksapce (fixes #42799)

* Fix #39417

* Use pseudo elements instead of mask-image so that labels retain subpixel AA

* Use ellipsis and disable fade for HC theme, and support hover colours

* Make requested changes and start on fixing transparency issue

* Merge all colours underneath tabs to fix transparency issue

* Rename color function, move workbench background into themes

* do not allow to change workbench background

* 💄

* fix npes and clean up

* fix class names

* remove blank line

* Open issue reporter in same display as workbench

* Styling updates

* Increase url length limit

* normalize extension ids before checking isEnabled

This reverts commit c63c92b8.