chore(noble): remove master staging branch

Author: mmstick

config/pop-os/24.04.mk

@@ -67,7 +67,7 @@ endif
 # Staging branches to use when building ISO.
 # No values is the same as building from release
 # `branch-name` is equivalent to `apt-manage add popdev:branch-name -y`
-STAGING_BRANCHES=master
+STAGING_BRANCHES=
 
 # Packages to have in live instance
 LIVE_PKGS=\