Minor edits to i3 variant

No need to explicitly list kali-themes in the packages to install, it's
pulled in anyway via the following dependency chain: kali-desktop-i3 ->
kali-desktop-core -> kali-themes

I removed the pulseaudio hook. I really don't see a reason to start
pulseaudio once, during the build process, as root. Plus, the second
line of the hook (rm -rf .pulse-cookieaa) has no effect, since there's
no file named .pulse-cookieaa. I added some debug logs to the hook to
confirm that.

kali-config/variant-i3/hooks/live/pulseaudio.chroot

@@ -1,4 +0,0 @@
-#!/bin/sh
-
-timeout 15 pulseaudio -vvv
-rm -rf .pulse-cookieaa

kali-config/variant-i3/package-lists/kali.list.chroot

@@ -14,7 +14,6 @@ kali-linux-default
 
 # Graphical desktop
 kali-desktop-i3
-kali-themes
 
 # Kali applications
 #<package>