Use the ClientFactory pattern everywhere replacing raw ClientBuilders.

# Conflicts:
#	ElementX/Sources/Services/UserSession/UserSessionStore.swift
#	NSE/Sources/NSEUserSession.swift

ElementX/Sources/Mocks/SDK/ClientBuilderSDKMock.swift

@@ -0,0 +1,24 @@
+//
+// Copyright 2026 Element Creations Ltd.
+//
+// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
+// Please see LICENSE files in the repository root for full details.
+//
+
+import Foundation
+import MatrixRustSDK
+import MatrixRustSDKMocks
+
+nonisolated extension ClientBuilderSDKMock {
+    struct Configuration {
+        var disableWellKnownLookup = false
+    }
+    
+    enum MockError: Error { case generic }
+    
+    convenience init(_ configuration: Configuration) {
+        self.init()
+        
+        disableWellKnownLookupDisableWellKnownLookupReturnValue = self
+    }
+}