Body scroll on empty promotion code add

[shopwareBot]

Description: When you click on the icon to send the "promotion code" in the offcanvas cart, but the promotion code is empty, then the body will scroll to the end.

Environment: Shopware 6.6.3.1 but it also occurs in a 6.5.6.1 shop And also tested it locally in a blank shop with shopware default theme

Steps to reproduce:

• Go to any shop
• put an item into the cart
• open the offcanvas cart
• click on the checkmark icon to add the promotion code but leave the input field blank

Expected result:

• display of an error message like it would do when you add an invalid code

Actual result:

• the body scrolls to the bottom and the only error message you get is from the browser that the input field is empty

[shopware-issue-bot[bot]]

We found the following existing issues which may help or are related to your topic:

• promotion note in offcanvas cart
• Overflow:hidden - body - position: fixed elements not working
• Inform a user that promotion codes may not be stacked
• Promotion code generation freezes brower tab
• [Github] Do not add promotion when cart price is zero
• Promotions are not applied to non-stackable items
• no display of an error message for promotion codes
• no display of an error message for promotion codes
• Missing features in promotions module
• Promotion disappears after saving empty form

[shopwareBot]

[public] Automated response: This issue is linked to the internal issue https://shopware.atlassian.net/browse/NEXT-37755.

[created from NEXT-37755, comment 487708]