[PWN-9343] Cancel rates update when view is disappeared

p2p_wallet/Scenes/Main/BankTransfer/WithdrawCalculator/WithdrawCalculatorView.swift

@@ -30,11 +30,15 @@ struct WithdrawCalculatorView: View {
             .padding(.horizontal, 16)
         }
         .onAppear {
+            viewModel.isViewAppeared.send(true)
             DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
                 // We need delay because BigInputView is UITextField
                 viewModel.isFromFirstResponder = true
             }
         }
+        .onDisappear {
+            viewModel.isViewAppeared.send(false)
+        }
     }
 
     var contentView: some View {

p2p_wallet/Scenes/Main/BankTransfer/WithdrawCalculator/WithdrawCalculatorViewModel.swift

@@ -24,6 +24,7 @@ final class WithdrawCalculatorViewModel: BaseViewModel, ObservableObject {
     let openBankTransfer = PassthroughSubject<Void, Never>()
     let openWithdraw = PassthroughSubject<StrigaWithdrawalInfo, Never>()
     let proceedWithdraw = PassthroughSubject<Void, Never>()
+    let isViewAppeared = PassthroughSubject<Bool, Never>()
 
     @Published var actionData = WithdrawCalculatorAction.zero
     @Published var isLoading = false
@@ -55,7 +56,6 @@ final class WithdrawCalculatorViewModel: BaseViewModel, ObservableObject {
 
     override init() {
         super.init()
-        loadRates()
         bindProperties()
         bindReachibility()
         bindAccounts()
@@ -190,6 +190,16 @@ private extension WithdrawCalculatorViewModel {
             .receive(on: RunLoop.main)
             .assignWeak(to: \.actionData, on: self)
             .store(in: &subscriptions)
+
+        isViewAppeared
+            .sink { [weak self] isAppeared in
+                if isAppeared {
+                    self?.loadRates()
+                } else {
+                    self?.cancelUpdate()
+                }
+            }
+            .store(in: &subscriptions)
     }
 
     func bindAccounts() {