Address the real lifetime issue of the SDK's Client by making Context.mediaProvider weak. (#4466)

This reverts commit 927aea4bfe.

ElementX/Sources/Services/Media/Provider/MediaLoader.swift

@@ -16,17 +16,7 @@ private final class MediaRequest {
 }
 
 actor MediaLoader: MediaLoaderProtocol {
-    // Something is holding onto our MediaProvider (and therefore this MediaLoader) which means
-    // when attempting to clear the caches, the SDK's Client hangs around and we end up with 2.
-    // I have spent a long time trying to understand what's going on – there's instances of both
-    // TimelineViewModel.Context and ComposerToolbarViewModel.Context still hanging around and
-    // a closure captures the media provider from both of those as far as I can tell, but I was
-    // unable to break the reference. Possibly related to the ElementTextView too.
-    //
-    // In lieu of the real fix, lets use a weak reference to the Client here so that it can be
-    // released and hopefully that will solve our logs files exploding in size when encountering
-    // a corrupt/missing database file.
-    private weak var client: ClientProtocol?
+    private let client: ClientProtocol
     private var ongoingRequests = [MediaSourceProxy: MediaRequest]()
 
     init(client: ClientProtocol) {
@@ -34,21 +24,18 @@ actor MediaLoader: MediaLoaderProtocol {
     }
     
     func loadMediaContentForSource(_ source: MediaSourceProxy) async throws -> Data {
-        try await enqueueLoadMediaRequest(forSource: source) { [weak client] in
-            guard let client else { throw MediaLoaderError.missingClient }
-            return try await client.getMediaContent(mediaSource: source.underlyingSource)
+        try await enqueueLoadMediaRequest(forSource: source) {
+            try await self.client.getMediaContent(mediaSource: source.underlyingSource)
         }
     }
     
     func loadMediaThumbnailForSource(_ source: MediaSourceProxy, width: UInt, height: UInt) async throws -> Data {
-        try await enqueueLoadMediaRequest(forSource: source) { [weak client] in
-            guard let client else { throw MediaLoaderError.missingClient }
-            return try await client.getMediaThumbnail(mediaSource: source.underlyingSource, width: UInt64(width), height: UInt64(height))
+        try await enqueueLoadMediaRequest(forSource: source) {
+            try await self.client.getMediaThumbnail(mediaSource: source.underlyingSource, width: UInt64(width), height: UInt64(height))
         }
     }
     
     func loadMediaFileForSource(_ source: MediaSourceProxy, filename: String?) async throws -> MediaFileHandleProxy {
-        guard let client else { throw MediaLoaderError.missingClient }
         let result = try await client.getMediaFile(mediaSource: source.underlyingSource,
                                                    filename: filename,
                                                    mimeType: source.mimeType ?? "application/octet-stream",

ElementX/Sources/Services/Media/Provider/MediaLoaderProtocol.swift

@@ -7,10 +7,6 @@
 
 import Foundation
 
-enum MediaLoaderError: Error {
-    case missingClient
-}
-
 // sourcery: AutoMockable
 protocol MediaLoaderProtocol {
     func loadMediaContentForSource(_ source: MediaSourceProxy) async throws -> Data

ElementX/Sources/Services/Media/Provider/MediaProvider.swift

@@ -9,7 +9,7 @@ import Combine
 import Kingfisher
 import UIKit
 
-struct MediaProvider: MediaProviderProtocol {
+class MediaProvider: MediaProviderProtocol {
     private let mediaLoader: MediaLoaderProtocol
     private let imageCache: Kingfisher.ImageCache
     private let networkMonitor: NetworkMonitorProtocol?

ElementX/Sources/Services/Media/Provider/MediaProviderProtocol.swift

@@ -17,7 +17,7 @@ enum MediaProviderError: Error {
 }
 
 // sourcery: AutoMockable
-protocol MediaProviderProtocol {
+protocol MediaProviderProtocol: AnyObject {
     func imageFromSource(_ source: MediaSourceProxy?, size: CGSize?) -> UIImage?
     func loadImageFromSource(_ source: MediaSourceProxy, size: CGSize?) async -> Result<UIImage, MediaProviderError>
     func loadImageDataFromSource(_ source: MediaSourceProxy) async -> Result<Data, MediaProviderError>