remove solution from shell > argument_check.md exercise (#10238)

topics/shell/argument_check.md

@@ -6,18 +6,4 @@ Note: assume the script is executed with an argument
 
 1. Write a script that will check if a given argument is the string "pizza"
  1. If it's the string "pizza" print "with pineapple?"
- 2. If it's not the string "pizza" print "I want pizza!"
-
-### Solution
-
-```
-/usr/bin/env bash
-
-arg_value=${1:-default}
-
-if [ $arg_value = "pizza" ]; then
-    echo "with pineapple?"
-else
-    echo "I want pizza!"
-fi
-```
+ 2. If it's not the string "pizza" print "I want pizza!"