observable for detecting if split view is active

[nielslyngsoe]

making an observable on contentDetailWorkspaceContext.splitView called splitViewActive which returns true when more than one variant is open.

[Copilot]

Pull Request Overview

This PR introduces an observable property named splitViewActive that determines if the split view is active based on whether more than one variant is present.

• Added splitViewActive observable derived from #activeVariantsInfo using a length check
• Updates the workspace split view manager controller to expose this new state

Comments suppressed due to low confidence (1)

src/Umbraco.Web.UI.Client/src/packages/core/workspace/controllers/workspace-split-view-manager.controller.ts:19

• Consider adding or updating tests to verify that splitViewActive correctly reflects the active split view state as the variants change.

public readonly splitViewActive = this.#activeVariantsInfo.asObservablePart((x) => x.length > 1);