Support on hover tooltip that is noninteractable even with interactable content

[PPakalns]

• Closes Noninteractive tooltip with any content (on_hover_ui) #5519
• I have followed the instructions in the PR template

[PPakalns]

Tested in real use case. Greatly reduces flickering for "preview" tooltips that may contain interactable widgets.

Use case: "Preview" of the page/window that will be opened if the button is pressed.

[github-actions]

Preview available at https://egui-pr-preview.github.io/pr/5543-noninteractivetooltip
Note that it might take a couple seconds for the update to show up after the preview_build workflow has completed.

[grtlr]

@emilk I ran into a related problem: rerun-io/rerun#8568

It seems like the current logic in should_show_hover_ui does not take into account that the tooltip is drawn in relation to the pointer position. Because of this, the tooltip always remains open since it's shifted at every frame.

In the case of the Rerun graph view, we can simply call on_hover_ui instead of on_hover_ui_at_pointer: rerun-io/rerun#8573