Do not hide media from your own user by default (#29797)

* Always show media from your own user

* Update usages of useMediaVisible

* lint

* Add a test for HideActionButton

* Improve docs

* Document the event

* fixup test

* Allow users to hide their own media if they wish.

* Update tests

* remove a check\

* tweak

* tweak

src/utils/MediaEventHelper.ts

@@ -117,7 +117,7 @@ export class MediaEventHelper implements IDestroyable {
     /**
      * Determine if the media event in question supports being hidden in the timeline.
      * @param event Any matrix event.
-     * @returns `true` if the media can be hidden, otherwise false.
+     * @returns `true` if the media can be hidden, otherwise `false`.
      */
     public static canHide(event: MatrixEvent): boolean {
         if (!event) return false;