Fix some warnings

Source/App/AppConfiguration+Data.swift

@@ -18,9 +18,12 @@ extension AppConfiguration {
     }
 
     static func from(_ data: Data) -> AppConfiguration? {
-        guard let object = try? NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(data) else { return nil }
-        let configuration = object as? AppConfiguration
-        if configuration == nil { Log.unexpected(.missingValue, "Configuration could not be unarchived") }
+        let unarchiver = try? NSKeyedUnarchiver(forReadingFrom: data)
+        unarchiver?.requiresSecureCoding = false
+        guard let configuration = unarchiver?.decodeObject(of: self, forKey: NSKeyedArchiveRootObjectKey) else {
+            Log.unexpected(.missingValue, "Configuration could not be unarchived")
+            return nil
+        }
         return configuration
     }
 }

Source/Controller/BlobViewController.swift

@@ -58,6 +58,10 @@ class BlobViewController: ContentViewController {
         forgetBlobCompletion()
 
         Task { @MainActor [weak self] in
+            guard let blob = self?.blob else {
+                return
+            }
+
             // cached image
             if let uiImage = Caches.blobs.image(for: blob) {
                 self?.imageView.image = uiImage

Source/Controller/LaunchViewController.swift

@@ -82,7 +82,7 @@ class LaunchViewController: UIViewController {
         }
 
         // if no configuration then onboard
-        guard var configuration = appConfiguration else {
+        guard let configuration = appConfiguration else {
             launchIntoOnboarding()
             return
         }

Source/Onboarding/Steps/JoinOnboardingStep.swift

@@ -34,7 +34,7 @@ import CrashReporting
         }
 
         Task { [weak self] in
-            var context: Onboarding.Context?
+            let context: Onboarding.Context?
 
             do {
                 context = try await Onboarding.createProfile(from: data)

Source/UI/Identity/ImageMetadataView.swift

@@ -67,7 +67,7 @@ fileprivate class ImageLoader: ObservableObject {
 
         await MainActor.run { [weak self] in
             guard let metadata = metadata, metadata.link != .null else {
-                isLoading = false
+                self?.isLoading = false
                 return
             }
 

Source/UI/ManageAliasView.swift

@@ -19,7 +19,7 @@ struct RoomAlias: Identifiable {
     var authorID: Int64
 
     var alias: String {
-        var components = string.replacingOccurrences(of: "https://", with: "")
+        let components = string.replacingOccurrences(of: "https://", with: "")
             .replacingOccurrences(of: "http://", with: "")
             .components(separatedBy: ".")
         return components.joined(separator: ".")