Fix loss of tree node state when switching views

This commit fixes an issue where the check state of categories was lost
when toggling between card and tree views. This is solved by immediately
emitting node state changes for all nodes. This ensures consistent view
transitions without any loss of node state information.

Furthermore, this commit includes added unit tests for the modified code
sections.

tests/unit/shared/Stubs/TreeNodeStateDescriptorStub.ts

@@ -12,7 +12,7 @@ export class TreeNodeStateDescriptorStub implements TreeNodeStateDescriptor {
 
   public isFocused = false;
 
-  public withFocusState(isFocused: boolean): this {
+  public withFocus(isFocused: boolean): this {
     this.isFocused = isFocused;
     return this;
   }
@@ -21,4 +21,9 @@ export class TreeNodeStateDescriptorStub implements TreeNodeStateDescriptor {
     this.checkState = checkState;
     return this;
   }
+
+  public withVisibility(isVisible: boolean): this {
+    this.isVisible = isVisible;
+    return this;
+  }
 }