Remove ember-classic-decorator package for Ember 5 compatibility

While upgrading our app to Ember 5.4.0 we encountered errors originating from `ember-light-table's` use of `ember-classic-decorator`. We found that the `ember-classic-decorator `package is not compatible with Ember 5.x.
See this [Discord thread](https://discord.com/channels/480462759797063690/1242438204943110184/1242439855695335456) for more context.

Opened a [PR](https://github.com/adopted-ember-addons/ember-light-table/pull/838) to remove it from the ember-light-table to make it work on Ember 5 projects.

Also found that `ember-scrollable` also uses `ember-classic-decorator`.
A reminder that the forked version of `ember-scrollable` by @RobbieTheWagner used in `ember-light-table's` has not been merged upstream yet.