Remove computed-property.override deprecation

I see this deprecation since Ember 3.9.0:

DEPRECATION: The <my-app@component:ember-modal-dialog/-tether-dialog::ember4138>#targetAttachmentClass computed property was just overriden. This removes the computed property and replaces it with a plain value, and has been deprecated. If you want this behavior, consider defining a setter which does it manually. [deprecation id: computed-property.override] See https://emberjs.com/deprecations/v3.x#toc_computed-property-override for more details.

I tried to identify where targetAttachmentClass was overridden but I can’t find it 🤷‍♂ Any clue?

[lukemelia]

I’m happy to review a PR to fix this but don’t have time to work on one myself currently.

[lukemelia]

Hi @jameshahn2, the reason for this error is that targetAttachmentClass is a computed property. If a value is passed in for the property, Ember’s historical behavior is that the passed value would replace the computed function. This is now deprecated, hence the warning. So we need a new way to provide a default value for targetAttachmentClass. I think that a way to do it would be to make the init method of the component(s) set targetAttachmentClass if and only if this.targetAttachmentClass is undefined.