fix(curriculum): Allow leading to zero before decimal point to be optional for opacity value (#37715)

* fix: allow-leading-zero-to-be-optional-before-decimal-point-for-opacity

* fix: use getComputedStyle intead of regex

Co-Authored-By: Tom <20648924+moT01@users.noreply.github.com>

curriculum/challenges/english/01-responsive-web-design/applied-visual-design/decrease-the-opacity-of-an-element.english.md

@@ -24,7 +24,7 @@ Set the <code>opacity</code> of the anchor tags to 0.7 using <code>links</code>
 ```yml
 tests:
   - text: Your code should set the <code>opacity</code> property to 0.7 on the anchor tags by selecting the class of <code>links</code>.
-    testString: assert(/\.links\s*\{[^}]+opacity\s*:\s*0.7;/.test(code));
+    testString: assert(getComputedStyle($('.links')[0]).opacity == '0.7');
 
 ```