fixed: relay detail view is not immediately available after adding new relay

Changelog-Fixed: relay detail view is not immediately available after adding new relay
Closes: https://github.com/damus-io/damus/issues/1369
Signed-off-by: Bryan Montz <bryanmontz@me.com>
Signed-off-by: William Casarin <jb55@jb55.com>

damus/Util/Relays/RelayModelCache.swift

@@ -7,7 +7,7 @@
 
 import Foundation
 
-final class RelayModelCache {
+final class RelayModelCache: ObservableObject {
     private var models = [RelayURL: RelayModel]()
     
     func model(withURL url: RelayURL) -> RelayModel? {
@@ -23,5 +23,6 @@ final class RelayModelCache {
     
     func insert(model: RelayModel) {
         models[model.url] = model
+        objectWillChange.send()
     }
 }

damus/Views/Relays/RelayView.swift

@@ -10,9 +10,17 @@ import SwiftUI
 struct RelayView: View {
     let state: DamusState
     let relay: String
+    @ObservedObject private var model_cache: RelayModelCache
     
     @Binding var showActionButtons: Bool
     
+    init(state: DamusState, relay: String, showActionButtons: Binding<Bool>) {
+        self.state = state
+        self.relay = relay
+        self.model_cache = state.relay_model_cache
+        _showActionButtons = showActionButtons
+    }
+    
     var body: some View {
         Group {
             HStack {
@@ -27,7 +35,7 @@ struct RelayView: View {
                 
                 RelayType(is_paid: state.relay_model_cache.model(with_relay_id: relay)?.metadata.is_paid ?? false)
                 
-                if let meta = state.relay_model_cache.model(with_relay_id: relay)?.metadata {
+                if let meta = model_cache.model(with_relay_id: relay)?.metadata {
                     Text(relay)
                         .background(
                             NavigationLink(value: Route.RelayDetail(relay: relay, metadata: meta), label: {