Entity Detail Workspace: First set isNew when data is set.

[nielslyngsoe]

First set isNew when data has been set.

Fixes #20544

[Copilot]

Pull Request Overview

This PR fixes a timing issue in the entity detail workspace where isNew was being set before the entity data was initialized. The fix ensures that when creating a scaffold for a new entity, the data (including unique identifier, persisted state, and current state) is set before marking the entity as new.

• Moved setIsNew(true) to be called after data initialization in the createScaffold method
• Prevents race conditions where UI components observing isNew might access uninitialized data

[madsrasmussen]

I am a little concerned about moving this around to solve a problem. I think the correct time for isNew to be set is as early as possible. We already know this information when the workspace is set up, which is why I don’t think this information should wait for data.

Doesn't this example show a solution without this fix? #20899