Add the same unsaved changes alerts that Android has. (#4803)

* Add an alert to Discard or Save when there are unsaved changes on the RoomDetailsEditScreen.

* Add an alert to Discard or Save when there are unsaved changes on the UserDetailsEditScreen.

* Add an alert to Discard or Save when there are unsaved changes on the SecurityAndPrivacyScreen.

* Update strings.

UnitTests/Sources/RoomDetailsEditScreenViewModelTests.swift

@@ -71,7 +71,7 @@ class RoomDetailsEditScreenViewModelTests: XCTestCase {
         XCTAssertFalse(context.viewState.canSave)
     }
     
-    func testSaveShowsSheet() {
+    func testAvatarPickerShowsSheet() {
         setupViewModel(roomProxyConfiguration: .init(name: "Some room", members: [.mockMeAdmin]))
         context.name = "name"
         XCTAssertFalse(context.showMediaSheet)
@@ -93,6 +93,47 @@ class RoomDetailsEditScreenViewModelTests: XCTestCase {
         XCTAssertEqual(action, .saveFinished)
     }
     
+    func testCancelWithoutChanges() async throws {
+        setupViewModel(roomProxyConfiguration: .init(name: "Some room", members: [.mockMeAdmin]))
+        XCTAssertFalse(context.viewState.canSave)
+        XCTAssertNil(context.alertInfo)
+        
+        var deferred = deferFulfillment(viewModel.actions) { $0 == .cancel }
+        context.send(viewAction: .cancel)
+        try await deferred.fulfill()
+        XCTAssertNil(context.alertInfo)
+    }
+    
+    func testCancelWithChangesAndDiscard() async throws {
+        setupViewModel(roomProxyConfiguration: .init(name: "Some room", members: [.mockMeAdmin]))
+        context.name = "name"
+        XCTAssertTrue(context.viewState.canSave)
+        XCTAssertNil(context.alertInfo)
+        
+        context.send(viewAction: .cancel)
+        
+        XCTAssertNotNil(context.alertInfo)
+        
+        let deferred = deferFulfillment(viewModel.actions) { $0 == .cancel }
+        context.alertInfo?.secondaryButton?.action?() // Discard
+        try await deferred.fulfill()
+    }
+    
+    func testCancelWithChangesAndSave() async throws {
+        setupViewModel(roomProxyConfiguration: .init(name: "Some room", members: [.mockMeAdmin]))
+        context.name = "name"
+        XCTAssertTrue(context.viewState.canSave)
+        XCTAssertNil(context.alertInfo)
+        
+        context.send(viewAction: .cancel)
+        
+        XCTAssertNotNil(context.alertInfo)
+        
+        let deferred = deferFulfillment(viewModel.actions) { $0 == .saveFinished }
+        context.alertInfo?.primaryButton.action?() // Save
+        try await deferred.fulfill()
+    }
+    
     func testErrorShownOnFailedFetchOfMedia() async throws {
         setupViewModel(roomProxyConfiguration: .init(name: "Some room", members: [.mockMeAdmin]))
         viewModel.didSelectMediaUrl(url: .picturesDirectory)