* Simplify how event content with captions are displayed
The caption component will now be added in `TimelineItemEventContentView` instead of separately in each `TimelineItem__View` component
* Make sure `CoilMediaFetcher` methods to fetch media throw errors
We need to catch them later to check if the content scanner marked some thumbnails or medias as invalid/unsafe in `AsyncImage` instances
* Add a `ContentScannerService` that allows us to manually scan a list of medias in an event and then update and store the results
The results take the form of `ContentValidationValue`, stored in a `ContentValidationState` instance tied to the event
* Create `EventContentValidationCache` to keep the `ContentValidationStates` for events in a room
* Expose `EventContentValidationCache` to Compose using `LocalEventContentValidationState`
Also add a couple of helper functions to avoid having to manually remember the states
* Use the new components to display invalid content in the timeline items
* Add `blurhash` to most media items so we can use it while validating the thumbnails/medias
* Fix custom layout issues with screenshot and UI tests
* Also check the validation state for replied-to events in the composer
* Fix and add tests
* Handle unrecoverable content validation errors too: display a 'not found' UI
* Improve the performance of `EqualWidthColumn` for the single item case
* Update screenshots
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Co-authored-by: ElementBot <android@element.io>
Jorge Martin Espinosa
0d03472c60