Changes in 0948d6b19e caused the post-bottom-ad component to start receiving the widget-ised 'transformedPost' instead of the original `post` model. In most cases this difference didn't matter, but it did cause noticable issues with `@model.category` and `@model.topic`.
This commit also deletes the unused `post-bottom/discourse-adplugin.hbs` connector. In the past, the adplugin itself was defining the post-bottom outlet. But now, we use RenderGlimmer to load the `post-bottom-ad` directly.
In the past, the ad plugin relied on two side-effects to achieve this behaviour:
1. Components being fully destroyed/rendered when navigating between pages. This stopped working when Discourse core moved to the more efficient 'loading slider' UI
2. The `listLoading` argument. This was an implementation detail of the old discovery routing infrastructure. Core recently overhauled this and removed the `listLoading` argument, because loading is now handled properly by the Ember router.
Instead of these two properties, we can use the `currentRoute` property of Ember's router service to trigger changes when navigating between pages. A common `{{#each` trick is used to fully destroy/re-render components even if the ad network is unchanged.
David Taylor