Update MinisiteValidateNoDeniedExtensionsTest.php

Closes #3459157

tests/src/Unit/MinisiteValidateNoDeniedExtensionsTest.php

@@ -38,7 +38,7 @@ final class MinisiteValidateNoDeniedExtensionsTest extends UnitTestCase {
     $form_state->clearErrors();
 
     // Test with the environment variable set.
-    putenv('DENIED_EXTENSIONS=jpg');
+    putenv('MINISITE_DENIED_EXTENSIONS=jpg');
     MinisiteItem::validateNoDeniedExtensions($element, $form_state);
     $errors = $form_state->getErrors();
     $this->assertNotEmpty($errors, 'Errors were expected but none found.');
@@ -48,7 +48,7 @@ final class MinisiteValidateNoDeniedExtensionsTest extends UnitTestCase {
     $form_state->clearErrors();
 
     // Test with the environment variable not set.
-    putenv('DENIED_EXTENSIONS');
+    putenv('MINISITE_DENIED_EXTENSIONS');
     MinisiteItem::validateNoDeniedExtensions($element, $form_state);
     $errors = $form_state->getErrors();
     $this->assertNotEmpty($errors, 'Errors were expected but none found.');