The dom.d.ts types changed to not allow null on the outline styles. I believe that setting this to empty string should be equivalent

Either extend `Disposable` or use a readonly `DispoableStore`

This reverts commit d0e1fe59.

Fixes #70577

fixes #54084

* Added `cachedScrollTop` to SCM panel

* Moved `cachedScrollTop` usage to `layoutBody()`