Migrate `button-class-vue` in `app/assets/javascripts/awards_handler.js`

Detected usage of gl-button class inside JS/Vue file. Please use the GlButton component from @gitlab/ui.

This should probably be tackled at the same time as #455658.

There are two ways to tackle this one:

• Short term fix: a solution similar to #455638 (closed) and #455642 (closed) (and previously !81552 (merged)).
• Long term fix: #418224 (comment 1469744888)