fix(curriculum): add test to check if the original variable is edited (#43791)

* fix: add test to check if variable is edited

* Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/regular-expressions/remove-whitespace-from-start-and-end.md

Co-authored-by: Nicholas Carrigan (he/him) <nhcarrigan@gmail.com>

Co-authored-by: Nicholas Carrigan (he/him) <nhcarrigan@gmail.com>

curriculum/challenges/english/02-javascript-algorithms-and-data-structures/regular-expressions/remove-whitespace-from-start-and-end.md

@@ -36,6 +36,12 @@ The `result` variable should not directly be set to a string
 assert(!code.match(/result\s*=\s*["'`].*?["'`]/));
 ```
 
+The value of the `hello` variable should not be changed.
+
+```js
+assert(hello === '   Hello, World!  ');
+```
+
 # --seed--
 
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