This is a line endings issue, but not from Ubuntu. Make sure you do have node and npm installed correctly by using the command:

sudo apt install nodejs npm

Then stop Windows path variables being shared with WSL by editing the /etc/wsl.conf file in WSL. If the file doesn't exist, execute sudo touch /etc/wsl.conf first. Edit the file with the command sudo nano /etc/wsl.conf and add the following configuration:

# Wsl.conf
[interop]
appendWindowsPath = false

Then restart WSL2 with command wsl --shutdown in Windows(Powershell or CMD).

alias ng="/usr/local/lib/node_modules/@angular/cli/bin/ng"

ln -s /usr/bin/nodejs /usr/bin/node

# The error message suggests that the script you're invoking has embedded \r characters,
# which in turn suggests that it has Windows-style \r\n line endings instead of the \n-only
# line endings bash expects.
# As a quick fix, you can remove the \r chars. as follows:
sed $'s/\r$//' ./install.sh > ./install.Unix.sh

Go inside android directory and run:
dos2unix ./gradlew