Move overviewRuler API under scrollbar

Fixes #5678

src/browser/Viewport.ts

@@ -62,7 +62,6 @@ export class Viewport extends Disposable {
     this._register(this._optionsService.onMultipleOptionChange([
       'scrollSensitivity',
       'fastScrollSensitivity',
-      'overviewRuler',
       'scrollbar'
     ], () => this._scrollableElement.updateOptions(this._getChangeOptions())));
     // Don't handle mouse wheel if wheel events are supported by the current mouse prototcol
@@ -135,7 +134,7 @@ export class Viewport extends Disposable {
     const showScrollbar = this._optionsService.rawOptions.scrollbar?.showScrollbar ?? true;
     const showArrows = this._optionsService.rawOptions.scrollbar?.showArrows ?? false;
     const verticalScrollbarSize = showScrollbar
-      ? (this._optionsService.rawOptions.overviewRuler?.width ?? ViewportConstants.DEFAULT_SCROLL_BAR_WIDTH)
+      ? (this._optionsService.rawOptions.scrollbar?.width ?? ViewportConstants.DEFAULT_SCROLL_BAR_WIDTH)
       : 0;
     return {
       mouseWheelScrollSensitivity: this._optionsService.rawOptions.scrollSensitivity,