Use MSC2530 filename when loading media

In the case of captioned images, the `body` of the event is the caption,
and is ill suited to be a filename. Often the caption can be
prohibitively long, causing the media to fail to load in some cases.

Fixes: https://github.com/element-hq/element-x-android/issues/2882
Signed-off-by: Joe Groocock <me@frebib.net>

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesFlowNode.kt

@@ -324,7 +324,7 @@ class MessagesFlowNode @AssistedInject constructor(
             is TimelineItemImageContent -> {
                 val navTarget = NavTarget.MediaViewer(
                     mediaInfo = MediaInfo(
-                        name = event.content.body,
+                        name = event.content.filename ?: event.content.body,
                         mimeType = event.content.mimeType,
                         formattedFileSize = event.content.formattedFileSize,
                         fileExtension = event.content.fileExtension
@@ -358,7 +358,7 @@ class MessagesFlowNode @AssistedInject constructor(
             is TimelineItemVideoContent -> {
                 val navTarget = NavTarget.MediaViewer(
                     mediaInfo = MediaInfo(
-                        name = event.content.body,
+                        name = event.content.filename ?: event.content.body,
                         mimeType = event.content.mimeType,
                         formattedFileSize = event.content.formattedFileSize,
                         fileExtension = event.content.fileExtension

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/components/event/TimelineItemImageView.kt

@@ -81,7 +81,13 @@ fun TimelineItemImageView(
                 modifier = Modifier
                     .fillMaxWidth()
                     .then(if (isLoaded) Modifier.background(Color.White) else Modifier),
-                model = MediaRequestData(content.preferredMediaSource, MediaRequestData.Kind.File(content.body, content.mimeType)),
+                model = MediaRequestData(
+                    source = content.preferredMediaSource,
+                    kind = MediaRequestData.Kind.File(
+                        body = content.filename ?: content.body,
+                        mimeType = content.mimeType,
+                    ),
+                ),
                 contentScale = ContentScale.Fit,
                 alignment = Alignment.Center,
                 contentDescription = description,

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/timeline/components/event/TimelineItemVideoView.kt

@@ -88,7 +88,13 @@ fun TimelineItemVideoView(
                 modifier = Modifier
                     .fillMaxWidth()
                     .then(if (isLoaded) Modifier.background(Color.White) else Modifier),
-                model = MediaRequestData(content.thumbnailSource, MediaRequestData.Kind.File(content.body, content.mimeType)),
+                model = MediaRequestData(
+                    source = content.thumbnailSource,
+                    kind = MediaRequestData.Kind.File(
+                        body = content.filename ?: content.body,
+                        mimeType = content.mimeType
+                    )
+                ),
                 contentScale = ContentScale.Fit,
                 alignment = Alignment.Center,
                 contentDescription = description,