### Godot version

Godot Engine v4.0.beta16.official.518b9e580

### System information

Linux, Vulkan, nvidia RTX 2070, Driver 525.60.11

### Issue description

Editor crashes when changing between theme editor and animation editor

Console:
`ERROR: Condition "slot >= slot_max" is true. Returning: nullptr
   at: get_instance (./core/object/object.h:962)
ERROR: Condition "slot >= slot_max" is true. Returning: nullptr
   at: get_instance (./core/object/object.h:962)

================================================================
handle_crash: Program crashed with signal 11
Engine version: Godot Engine v4.0.beta16.official (518b9e5801a19229805fe837d7d0cf92920ad413)
Dumping the backtrace. Please include this when reporting the bug to the project developer.
[1] /lib/x86_64-linux-gnu/libc.so.6(+0x42520) [0x7f908134c520] (??:0)
[2] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x1c6d494] (??:0)
[3] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x1c4eefe] (??:0)
[4] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x44fb21a] (??:0)
[5] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x26faf8b] (??:0)
[6] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x448c994] (??:0)
[7] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2a9eb11] (??:0)
[8] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2a9eb8f] (??:0)
[9] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x1c65ae0] (??:0)
[10] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x42e50c2] (??:0)
[11] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x44fb21a] (??:0)
[12] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2bcf06f] (??:0)
[13] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2bcfa7e] (??:0)
[14] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2b30f15] (??:0)
[15] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2b817d5] (??:0)
[16] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2b85781] (??:0)
[17] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2b85deb] (??:0)
[18] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x2ba1cf5] (??:0)
[19] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0xe69114] (??:0)
[20] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x42d5f34] (??:0)
[21] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0x42d6db5] (??:0)
[22] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0xe6ab2d] (??:0)
[23] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0xddd7c2] (??:0)
[24] /lib/x86_64-linux-gnu/libc.so.6(+0x29d90) [0x7f9081333d90] (??:0)
[25] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x80) [0x7f9081333e40] (??:0)
[26] /home/solorvox/GameDev/godot-engine/Godot_v4.0-beta16_linux.x86_64() [0xdfd8ee] (??:0)
-- END OF BACKTRACE --
================================================================`


### Steps to reproduce

Open included project
1) Click on AnimationPlayer in scene tree
2) Click on TextureRect in scene tree
4) Click on "Theme" editor at bottom of editor window (theme editor opens)
5) Click on "Animation" editor at bottom (crash)

Notes: The shader source code must be open, and a theme must be open to repeat this crash

### Minimal reproduction project

[animation-crash.zip](https://github.com/godotengine/godot/files/10530646/animation-crash.zip)

void _dock_select_draw();
	void _dock_pre_popup(int p_which);
	void _dock_split_dragged(int ofs);
	void _dock_popup_exit();
	void _dock_floating_close_request(Control *p_control);
	void _dock_make_float();
	void _scene_tab_changed(int p_tab);
	void _scene_tab_closed(int p_tab, int option = SCENE_TAB_CLOSE);
	void _scene_tab_hovered(int p_tab);
	void _scene_tab_exit();
	void _scene_tab_input(const Ref<InputEvent> &p_input);
	void _reposition_active_tab(int idx_to);
	void _thumbnail_done(const String &p_path, const Ref<Texture2D> &p_preview, const Ref<Texture2D> &p_small_preview, const Variant &p_udata);
	void _scene_tab_script_edited(int p_tab);
	Dictionary _get_main_scene_state();
	void _set_main_scene_state(Dictionary p_state, Node *p_for_scene);
	int _get_current_main_editor();
	void _save_docks();
	void _load_docks();
	void _save_docks_to_config(Ref<ConfigFile> p_layout, const String &p_section);
	void _load_docks_from_config(Ref<ConfigFile> p_layout, const String &p_section);
	void _update_dock_slots_visibility(bool p_keep_selected_tabs = false);
	void _dock_tab_changed(int p_tab);
	void _save_open_scenes_to_config(Ref<ConfigFile> p_layout, const String &p_section);
	void _load_open_scenes_from_config(Ref<ConfigFile> p_layout, const String &p_section);
	void _update_layouts_menu();
	void _layout_menu_option(int p_id);
	void _update_addon_config();
	void _toggle_distraction_free_mode();
	void _inherit_imported(const String &p_action);