1922 live view emit dir structure on load (#1923)

docs/release_notes/next/fix-1922-live_view_image_load_on_init

@@ -0,0 +1 @@
+#1922 : Load images into live viewer on initialisation if images already present in selected directory.

mantidimaging/gui/windows/live_viewer/model.py

@@ -100,7 +100,7 @@ def path(self, path: Path) -> None:
         self._dataset_path = path
         self.image_watcher = ImageWatcher(path)
         self.image_watcher.image_changed.connect(self._handle_image_changed_in_list)
-        self.image_watcher.find_images()
+        self.image_watcher._handle_directory_change("")
 
     def _handle_image_changed_in_list(self, image_files: list[Image_Data]) -> None:
         """

mantidimaging/gui/windows/live_viewer/view.py

@@ -32,15 +32,14 @@ def __init__(self, main_window: 'MainWindowView', live_dir_path: Path) -> None:
         self.presenter = LiveViewerWindowPresenter(self, main_window)
         self.live_viewer = LiveViewWidget()
         self.imageLayout.addWidget(self.live_viewer)
+        self.live_viewer.z_slider.valueChanged.connect(self.presenter.select_image)
 
     def show(self) -> None:
         """Show the window"""
         super().show()
         self.activateWindow()
         self.watch_directory()
 
-        self.live_viewer.z_slider.valueChanged.connect(self.presenter.select_image)
-
     def show_most_recent_image(self, image: np.ndarray) -> None:
         """
         Show the most recently modified image in the image view.