Enable wsl to reimport Linux distros that got unregistered due to laptop resetting to factory defaults

Is your feature request related to a problem? Please describe.
I had a version upgrade on windows 10 (now it is on Microsoft Windows [Version 10.0.18363.836]).
I faced some problems and I reset my laptop to factory defaults. WSL got uninstalled after this.
I reinstalled WSL after laptop reset, I am unable to use the linux distros I imported before the laptop reset

Describe the solution you'd like
WSL has '--unregister' option but there is no '--register' option.
The --import option does not allow to reimport previoulsy imported distro.

Describe alternatives you've considered
wsl --register or wsl --repair option to detect a 'rootfs' folder and compare it with an image (say, 'ubuntu-20.04-server-cloudimg-amd64-wsl.rootfs.tar.gz) and register it without overwriting the contents. I don't want WSL to overwrite all my linux files from the image file. It just has to recognize and register the given folder as a valid linux distro

Start by reviewing the existing WSL --import and --unregister command behavior described in the issue. Determine how a previously imported rootfs could be recognized and registered without overwriting its contents; done means a supported reimport or repair path restores the distro after unregistering.