UI test cleanup (#2598)

* Stop running the UI tests on the double localized pseudolanguage

* Fix UI tests signalling comms problem because the json key ordering wasn't defined and the messages wouldn't match.

* Remove UI tests that are now the same as preview tests (i.e. non flow based, only screen based), fixed the rest so they run on iOS 17.2, the iPhone 15 and iPad 10th gen simulators.

* Remove unnecessary gitignore instructions, change UI test snapshot naming convention to be more similar to the unit test ones

* Enable derived data and spm checkout caching for UI tests

* Switch UI tests back to the perf-only runner, moved the integration tests to the iPhone 15 Pro simulator.

* Address PR comments

UITests/Sources/Application.swift

@@ -19,6 +19,8 @@ import XCTest
 
 enum Application {
     static func launch(_ identifier: UITestsScreenIdentifier, disableTimelineAccessibility: Bool = true) -> XCUIApplication {
+        checkEnvironments()
+        
         let app = XCUIApplication()
         
         var launchEnvironment = [
@@ -33,6 +35,22 @@ enum Application {
         app.launch()
         return app
     }
+    
+    private static func checkEnvironments() {
+        let requirediPhoneSimulator = "iPhone15,4" // iPhone 15
+        let requirediPadSimulator = "iPad13,18" // iPad (10th generation)
+        let requiredOSVersion = 17
+        
+        let osVersion = ProcessInfo().operatingSystemVersion
+        guard osVersion.majorVersion == requiredOSVersion else {
+            fatalError("Switch to iOS \(requiredOSVersion) for these tests.")
+        }
+        
+        guard let deviceModel = ProcessInfo().environment["SIMULATOR_MODEL_IDENTIFIER"],
+              deviceModel == requirediPhoneSimulator || deviceModel == requirediPadSimulator else {
+            fatalError("Switch to using \(requirediPhoneSimulator) or \(requirediPadSimulator) for these tests.")
+        }
+    }
 }
 
 extension XCUIApplication {
@@ -46,6 +64,8 @@ extension XCUIApplication {
         if let step {
             snapshotName += "-\(step)"
         }
+        
+        snapshotName += "-\(deviceName)-\(localeCode)"
 
         // Sometimes the CI might be too slow to load the content so let's wait the delay time
         try await Task.sleep(for: delay)
@@ -56,24 +76,21 @@ extension XCUIApplication {
             snapshot = snapshot.inset(by: insets)
         }
 
-        let failure = verifySnapshot(matching: snapshot,
+        let failure = verifySnapshot(of: snapshot,
                                      as: .image(precision: precision,
                                                 perceptualPrecision: 0.98,
                                                 scale: nil),
-                                     named: snapshotName,
-                                     testName: testName)
-
+                                     // use any kind of suffix here to snapshot the same file multiple times and avoid countering on the library side
+                                     named: "UI",
+                                     testName: snapshotName)
+        
         if let failure,
            !failure.contains("No reference was found on disk."),
            !failure.contains("to test against the newly-recorded snapshot") {
             XCTFail(failure)
         }
     }
-
-    private var testName: String {
-        localeCode + "-" + deviceName
-    }
-
+    
     private var deviceName: String {
         var name = UIDevice.current.name