WPF-942564: Add details about saving the layout and where to call the SaveDockState on DockingManager

[Karthick-Arjunan]

Description:

Added the content for saving autoPersist state in the DockingManager.

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: 942564-hotfix

[SyncfusionBuild]

CI Status: FAILURE ❌
Source Compilation: SUCCESS ✅
Failure Reason: CI Failure with violation
Build Location: 942564-hotfix
Technical Error(s): 0
Spelling Error(s): 0
Image Alt Text Error(s): 0
Image Size Error(s): 0
Image Name Error(s): 0
Front matter Error(s): 1
File Path Error(s): 0
CodeSnippet File Path Missing Error(s): 0
Toc Anchor Tags Validation Error(s): 0
MD Tag Validation Error(s): 0

[SyncfusionBuild]

Build Status: INPROGRESS 🔃
Build Location: 942564-hotfix

[SyncfusionBuild]

CI Status: SUCCESS ✅
Source Compilation: SUCCESS ✅
Build Location: 942564-hotfix
Technical Error(s): 0
Spelling Error(s): 0
Image Alt Text Error(s): 0
Image Size Error(s): 0
Image Name Error(s): 0
Front matter Error(s): 0
File Path Error(s): 0
CodeSnippet File Path Missing Error(s): 0
Toc Anchor Tags Validation Error(s): 0
MD Tag Validation Error(s): 0

[durga-muthu]

When PersistState is set to true, the save operation is handled automatically, as clearly documented. In that case, manually saving the layout becomes redundant. So, why should we explicitly save the layout when PersistState is already enabled?