Help youtube video loads without even having the help modal open (#3169)

## Description:

Title

## Please complete the following:

- [X] I have added screenshots for all UI updates
- [X] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [X] I have added relevant tests to the test directory
- [X] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

FloPinguin

src/client/HelpModal.ts

@@ -153,7 +153,7 @@ export class HelpModal extends BaseModal {
               <iframe
                 id="tutorial-video-iframe"
                 class="absolute top-0 left-0 w-full h-full"
-                src="${TUTORIAL_VIDEO_URL}"
+                src="${this.isModalOpen ? TUTORIAL_VIDEO_URL : ""}"
                 title="${translateText("help_modal.video_tutorial_title")}"
                 frameborder="0"
                 allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share"