Event Permalink Tweaks (#2754)

* Handle errors focussing the timeline.

* Add a test for focussing on an existing timeline item.

UITests/Sources/RoomScreenUITests.swift

@@ -109,6 +109,25 @@ class RoomScreenUITests: XCTestCase {
         
         try await app.assertScreenshot(.roomLayoutBottom, step: 1)
     }
+    
+    func testTimelineLayoutHighlightExisting() async throws {
+        let client = try UITestsSignalling.Client(mode: .tests)
+        
+        let app = Application.launch(.roomLayoutHighlight)
+        
+        await client.waitForApp()
+        defer { try? client.stop() }
+        
+        // Some time for the timeline to settle.
+        try await Task.sleep(for: .seconds(1))
+        // When tapping a permalink to an item in the timeline.
+        try await performOperation(.focusOnEvent("$5"), using: client)
+        // Some time for the timeline to settle.
+        try await Task.sleep(for: .seconds(1))
+        
+        // Then the item should become highlighted.
+        try await app.assertScreenshot(.roomLayoutHighlight, step: 0)
+    }
 
     func testTimelineReadReceipts() async throws {
         let app = Application.launch(.roomSmallTimelineWithReadReceipts)

UITests/Sources/__Snapshots__/Application/roomLayoutHighlight-0-iPad-10th-generation-en-GB.UI.png

@@ -0,0 +1,3 @@
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+size 233181

UITests/Sources/__Snapshots__/Application/roomLayoutHighlight-0-iPhone-15-en-GB.UI.png

@@ -0,0 +1,3 @@
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+oid sha256:79e3b444b2682f3697c1f27c898be7a3ed50d230c60d5c0fd33bfe9125056802
+size 331437