Importing directory of images over-extends Godot's RAM usage

### Tested versions

4.2.2

### System information

Windows 7

### Issue description

If you import a directory with lots of images, Godot will "helpfully" try and do it in parallel; makes sense for most game assets. However, the import process for even one large image file uses huge amounts of RAM, so when Godot tries to do multiple files in parallel, it can easily end up using far more RAM than the system has.

Godot does this self-induced lack of RAM well. It can crash Godot (not predictably reproduceable), crash Windows (not predictably reproduceable), and do weird stuff to the interface after the import is completed (below; not predictably reproduceable).


### Steps to reproduce

1) Create a new Project
2) Import a directory of large images. In my case I'm using about 22 Hubble Pictures

3) Godot Analyses the images, using 12GB or so of RAM.

If I double the number of images (copy/paste onto themselves), sure enough, Godot now uses 20GB of RAM, which is more than the 16GB on my system, so lots of paging and Bad Things (tm) can happen.

I expect if I had a directory filled solely with a couple dozen of the very largest of those images, Godot would do awful things to my RAM. Someone else can test that. :-)
You can get some Hubble pictures from here if you're struggling for large images to test against: https://hubblesite.org/images

### Minimal reproduction project (MRP)

N/A