Closes #22447

When navigate forward/back, the focus moves from the ProjectSearchView's result editor to the Pane, and then move to the ProjectSearchView, but the event on_focus_in not triggered for ProjectSearchView, causing the result editor to lose focus eventually.

Considering that the navigation might be triggered again in the next frame, so use on_next_frame in on_focus event to move focus to result editor.

Next frame:

• the blur event triggered for result editor.
• focus move from ProjectSearchView to result editor in on_focus event for ProjectSearchView
• navigate again, focus moves from result editor to Pane then move back to ProjectSearchView
• the focus not change during this frame, so no focus event happened for ProjectSearchView.

Release Notes:

• Fix lost focus when navigate back in project search result