Fix #8649: Improve Performance of Select Token to Send (#8654)

* Update performance of `SelectAccountTokenStore`; build account sections for changes instead of computed property

* Fix for case where balance is 0 after being cached as non-zero does not update cache, don't lose cached balances after failed response.

Sources/BraveWallet/Crypto/BuySendSwap/SendTokenView.swift

@@ -300,7 +300,7 @@ struct SendTokenView: View {
         didAutoShowSelectAccountToken = true
       }
       sendTokenStore.update()
-      await sendTokenStore.selectTokenStore.update()
+      sendTokenStore.selectTokenStore.setup()
     }
     .navigationViewStyle(.stack)
   }

Sources/BraveWallet/Crypto/SelectAccountTokenView.swift

@@ -30,11 +30,11 @@ struct SelectAccountTokenView: View {
 
   var body: some View {
     List {
-      if store.accountSections.isEmpty {
+      if !store.isSetup {
         // Fetching accounts & assets. Typically won't see this.
         ProgressView()
           .listRowBackground(Color(.secondaryBraveGroupedBackground))
-      } else if store.filteredAccountSections.flatMap(\.tokenBalances).isEmpty && !store.isLoadingBalances {
+      } else if store.accountSections.isEmpty && !store.isLoadingBalances {
         Text(Strings.Wallet.selectTokenToSendNoTokens)
           .font(.headline.weight(.semibold))
           .foregroundColor(Color(.braveLabel))
@@ -80,7 +80,7 @@ struct SelectAccountTokenView: View {
     if !store.isHidingZeroBalances {
       return true
     }
-    return store.filteredAccountSections.flatMap(\.tokenBalances).isEmpty
+    return store.accountSections.isEmpty
   }
 
   private var networkFilterButton: some View {
@@ -110,7 +110,7 @@ struct SelectAccountTokenView: View {
   }
 
   private var accountSections: some View {
-    ForEach(store.filteredAccountSections) { accountSection in
+    ForEach(store.accountSections) { accountSection in
       Section(
         content: {
           if accountSection.tokenBalances.isEmpty {