Fix image cropper not closing correctly

Originally it gives the following error:

Uncaught (in promise) TypeError: e.destroy is not a function
    submit image_cropper.js:80
    promise callback*submit image_cropper.js:80
    1 image_cropper.vue:17
    s runtime-core.esm-bundler.js:155
    u runtime-core.esm-bundler.js:164
    n runtime-dom.esm-bundler.js:373
    y runtime-dom.esm-bundler.js:316
    _ runtime-dom.esm-bundler.js:334

the destroy method should be named as-is, as it's not the lifecycle function right?

merged

mentioned in commit c2a4051d