Changing the 'Import As' of a PNG file to 'AtlasTexture' not working cleanly post 4.2

[LakshayaG73]

Tested versions

Reproducible in 4.2

System information

Windows 10 - Godot 4.2

Issue description

In 4.1, changing the 'Import as' of a Texture to an AtlasTexture, would restart the editor, and everything would work post restart.

Now, doing this does not restart the editor, and the new atlas file does not show up in the filesystem until a forced restart.

Post restart, the atlas file shows up, but any place the Texture was used pre change of 'Import as' gets corrupted, and you have to remake the animations.

Steps to reproduce

1. Import few png images into a fresh project
2. Create an AnimatedSprite node, and add these png images into an animation
3. Select all the png images, and change the 'Import As' to 'AtlasTexture', and follow the remaining steps to do so
4. The images will no longer be visible with the node, and post editor restart, the sprite frames resource will have no images in it.

Minimal reproduction project (MRP)

It will only reproduce once. Difficult to create an MRP.

Edit(lyuma): MRP was attached by KoBeWi to #85977 : https://github.com/godotengine/godot/files/13625635/AtlasTest.zip
Instructions: "Select both icon files and change import type to TextureAtlas, then save the scene."

[clayjohn]

CC @KoBeWi This is likely a result of #78890

[KoBeWi]

Ok so
The bug is caused by SpriteFrames' textures being inside an array. The replacing method does not check inside arrays and thus the old resource is not replaced.
You can workaround the bug by not saving the scene after reimport. Instead you should reload it, or better, don't have it opened.

The file not appearing can be fixed by calling scan(), but for whatever reason this does not prevent some errors from being printed (about a missing file).