Refine workspace document transition test semantics

Agent-Logs-Url: https://github.com/PowerShell/PowerShellEditorServices/sessions/f6b6da25-a6a1-4158-9738-3a65a7e3008e

Co-authored-by: JustinGrote <15258962+JustinGrote@users.noreply.github.com>

Author: Copilot

test/PowerShellEditorServices.Test/Extensions/EditorOperationsServiceTests.cs

@@ -68,15 +68,18 @@ public void GetWorkspaceOpenDocumentsTracksEditedAndUntitledSaveStates()
 
             openSaved.ApplyChange(new FileChange
             {
-                IsReload = true,
+                Line = 1,
+                Offset = 1,
+                EndLine = 1,
+                EndOffset = 1,
                 InsertString = "Set-StrictMode -Version Latest"
             });
 
             WorkspaceOpenDocument[] editedDocuments = editorOperationsService.GetWorkspaceOpenDocuments();
             Assert.Contains(editedDocuments, static document => document.Path.EndsWith("open-saved.ps1") && !document.Saved);
 
-            openSaved.IsInMemory = openSaved.IsUntitled;
-            openUntitled.IsInMemory = openUntitled.IsUntitled;
+            SimulateSaveReset(openSaved);
+            SimulateSaveReset(openUntitled);
 
             WorkspaceOpenDocument[] savedDocuments = editorOperationsService.GetWorkspaceOpenDocuments();
             Assert.Contains(savedDocuments, static document => document.Path.EndsWith("open-saved.ps1") && document.Saved);
@@ -88,5 +91,10 @@ private static ScriptFile CreateFileBuffer(WorkspaceService workspaceService, st
             string filePath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N"), fileName);
             return workspaceService.GetFileBuffer(DocumentUri.FromFileSystemPath(filePath), initialBuffer: string.Empty);
         }
+
+        private static void SimulateSaveReset(ScriptFile scriptFile)
+        {
+            scriptFile.IsInMemory = scriptFile.IsUntitled;
+        }
     }
 }