Fix crash browsing file/directory properties within popups

Caused by [0] which closed all popups when adding a file selector event.

This was done so pressing "Open..." from the splash closes the splash
however it caused BUTTONS_OT_file_browse & BUTTONS_OT_directory_browse
to crash when changing the path of an RNA property within a popup.

Move the logic to close popups into the splash screen itself.
Since some actions such as opening a URL's should keep the splash open,
resolve by closing the splash when a file selector is opened.

[0]: b49abbec5f

source/blender/windowmanager/intern/wm_event_system.cc

@@ -4298,9 +4298,6 @@ void WM_event_add_fileselect(bContext *C, wmOperator *op)
   ScrArea *root_area = nullptr;
   ARegion *root_region = nullptr;
 
-  /* Close any popups, like when opening a file browser from the splash. */
-  UI_popup_handlers_remove_all(C, &root_win->modalhandlers);
-
   /* Setting the context window unsets the context area & screen. Avoid doing that, so operators
    * calling the file browser can operate in the context the browser was opened in. */
   if (ctx_win != root_win) {

source/blender/windowmanager/intern/wm_splash_screen.cc

@@ -170,6 +170,30 @@ static ImBuf *wm_block_splash_image(int width, int *r_height)
   return ibuf;
 }
 
+/**
+ * Close the splash when opening a file-selector.
+ */
+static void wm_block_splash_close_on_fileselect(bContext *C, void *arg1, void * /*arg2*/)
+{
+  wmWindow *win = CTX_wm_window(C);
+  if (!win) {
+    return;
+  }
+
+  /* Check for the event as this will run before the new window/area has been created. */
+  bool has_fileselect = false;
+  LISTBASE_FOREACH (const wmEvent *, event, &win->event_queue) {
+    if (event->type == EVT_FILESELECT) {
+      has_fileselect = true;
+      break;
+    }
+  }
+
+  if (has_fileselect) {
+    wm_block_close(C, arg1, nullptr);
+  }
+}
+
 static uiBlock *wm_block_create_splash(bContext *C, ARegion *region, void * /*arg*/)
 {
   const uiStyle *style = UI_style_get_dpi();
@@ -234,6 +258,8 @@ static uiBlock *wm_block_create_splash(bContext *C, ARegion *region, void * /*ar
     mt = WM_menutype_find("WM_MT_splash", true);
   }
 
+  UI_block_func_set(block, wm_block_splash_close_on_fileselect, block, nullptr);
+
   if (mt) {
     UI_menutype_draw(C, mt, layout);
   }