The install fails when there is no "ls" alias

"ls" should never have been aliased in the first place. It was a mistake. The emacs install de-aliases it unconditionally. Except I've done that on my platform, so the "unalias ls" command fails and that causes the installation to fail. Killing the alias is reasonable enough, but the install script needs to ignore the failure or test for the existence of the alias first.

unalias ls || :

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: emacs 1:27.1+1-3ubuntu3
ProcVersionSignature: Ubuntu 5.13.0-30.33-generic 5.13.19
Uname: Linux 5.13.0-30-generic x86_64
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: KDE
Date: Tue Mar 8 10:45:08 2022
InstallationDate: Installed on 2022-02-09 (26 days ago)
InstallationMedia: Ubuntu 21.10 "Impish Indri" - Release amd64 (20211012)
PackageArchitecture: all
SourcePackage: emacs
UpgradeStatus: No upgrade log present (probably fresh install)