### Godot version

master

### System information

Godot v4.2.beta (0ea75d77c) - Windows 10.0.22621 - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 2070 (NVIDIA; 31.0.15.3598) - Intel(R) Core(TM) i7-10750H CPU @ 2.60GHz (12 Threads)

### Issue description

When any of the Import, Filesystem, Node, or History docks are floating, changing an editor feature crashes the engine.
Changing any setting or selecting a different profile triggers it.

This is because `EditorNode::_feature_profile_changed` assumes the docks are in a `TabContainer`, and if they are floating they aren't in one.


### Steps to reproduce

Make any of these docks floating: Import, Filesystem, Node, or History
Open Editor Features (Editor -> Manage Editor Features...)
Make a profile (if you have none) or change a setting on the existing profile

### Minimal reproduction project

n/a
Ref<Image> img;
		
		
		
		if (c3d == 0 && c2d == 0) {
			img.instantiate();
			img->initialize_data(1, 1, false, Image::FORMAT_RGB8);
		} else if (c3d < c2d) {
			Ref<ViewportTexture> viewport_texture = scene_root->get_texture();
			if (viewport_texture->get_width() > 0 && viewport_texture->get_height() > 0) {
				img = viewport_texture->get_image();
			}
		} else {
			
			
			
			Ref<EditorFeatureProfile> profile = feature_profile_manager->get_current_profile();
			if (!profile.is_valid() || !profile->is_feature_disabled(EditorFeatureProfile::FEATURE_3D)) {
				img = Node3DEditor::get_singleton()->get_editor_viewport(0)->get_viewport_node()->get_texture()->get_image();
			}
		}
		if (img.is_valid() && img->get_width() > 0 && img->get_height() > 0) {
			img = img->duplicate();
			save.step(TTR("Creating Thumbnail"), 2);
			save.step(TTR("Creating Thumbnail"), 3);
			int preview_size = EDITOR_GET("filesystem/file_dialog/thumbnail_size");
			preview_size *= EDSCALE;
			
			int vp_size = MIN(img->get_width(), img->get_height());