fix(installer): don't use sudo when user is in Termux (#11591)

Co-authored-by: Marc Cornellà <hello@mcornella.com>

tools/install.sh

@@ -84,6 +84,11 @@ command_exists() {
 user_can_sudo() {
   # Check if sudo is installed
   command_exists sudo || return 1
+  # Termux can't run sudo unless the device is rooted. Either way, `chsh` works
+  # without sudo, so we can detect it and exit the function early.
+  case "$PREFIX" in
+  *com.termux*) return 1 ;;
+  esac
   # The following command has 3 parts:
   #
   # 1. Run `sudo` with `-v`. Does the following: