Animation panel: moving cursor to Scene view focuses it, preventing further use of Animation keyboard shortcuts

### Tested versions

- Reproducible in v4.2.1.stable.official [b09f793f5], v4.2.2.stable.official [15073afe3], v4.3.rc2.official [3978628c6]

### System information

Godot v4.2.1.stable - Ubuntu 22.04.4 LTS 22.04 - X11 - Vulkan (Mobile) - dedicated NVIDIA GeForce GTX 860M (nvidia; 535.161.07) - Intel(R) Core(TM) i7-4710HQ CPU @ 2.50GHz (8 Threads)

### Issue description

When using the animation panel and focusing it (either the overall panel or a specific track and key) in order to use animation contextual shortcuts (such as Ctrl+Left/Right to move to previous/next step), and moving the cursor away to hover the Scene view, the Scene view will immediately be focused, preventing further use of Animation keyboard shortcuts.

This seems by design, maybe to allow Scene view shortcuts like W to switch to Translate mode; but no other panel does this, and therefore going back to the Animation panel is not even enough to focus the Animation panel again, you must click on it.

While this seems benign, I have a real use case where it bothers me a lot: I'm trying to estimate the number of pixels a sprite is moving by during some animation. I use my cursor as a reference for the initial pixel position. Then I use Ctrl+Right to advance the animation, and compare the cursor to the next pixel position. But moving the cursor focuses the Scene view and prevents me from advancing the animation. I have to play the animation very slowly while having the cursor over the Scene view, or inspect the animation directly in my graphics editor, to do what I want.

If it's an intended behavior then I'd like an option to disable it (I can reopen a feature request in this case).

### Steps to reproduce

1. Create some Animation and open the Animation Panel
2. Add some track to test Ctrl+Left/Right shortcuts
3. Move cursor to hover Scene view (without clicking)
4. Observe focus switching to Scene view (blue frame highlight + Animation contextual shortcuts stop working)

### Minimal reproduction project (MRP)

N/A

Start by reproducing the focus change between the Animation panel and Scene view using the listed Ctrl+Left/Right shortcut steps. Trace the Animation panel and Scene view focus handling, then confirm the intended behavior with maintainers; done means the agreed focus behavior no longer blocks the documented Animation shortcuts.

Written by the indexing model from the issue text.