delete is no primary action from enlarged images

[r10s]

On enlarged images, delete is not a primary action many ppl want to go for, it is more intuitive in the menu.

this is also what other messengers are doing.

(this commit was extracted from https://github.com/deltachat/deltachat-android/pull/3212

[github-actions[bot]]

To test the changes in this pull request, install this apk: 📦 app-preview.apk