profile.d/toolbox.sh: set bash PS1 as explicit string constant

since it is constant there is no need to use printf and embed
binary color codes, which also made it hard to match on toolbox PS1.

Signed-off-by: Jens Petersen <[email protected]>

#1514

Author: juhp

profile.d/toolbox.sh

@@ -48,7 +48,7 @@ fi
 
 if [ -f /run/.containerenv ] \
    && [ -f /run/.toolboxenv ]; then
-    [ "${BASH_VERSION:-}" != "" ] && PS1=$(printf "\[\033[35m\]⬢\[\033[0m\]%s" "[\u@\h \W]\\$ ")
+    [ "${BASH_VERSION:-}" != "" ] && PS1='\[\e[35m\]⬢\[\e[0m\][\u@\h \W]\$ '
     [ "${ZSH_VERSION:-}" != "" ] && PS1=$(printf "\033[35m⬢\033[0m%s" "[%n@%m]%~%# ")
 
     if ! [ -f "$toolbox_welcome_stub" ]; then