Prevent sendProviderMessage calls when not necessary (#858)

Task/Issue URL: https://app.asana.com/0/1207603085593419/1207629954356116/f

iOS PR: duckduckgo/iOS#2979
macOS PR: duckduckgo/macos-browser#2892

What kind of version bump will this require?: Patch

## Description

The VPN toggle is sometimes failing silently, apparently due to a race condition created by calls to `sendProviderMessage` while the VPN is starting up.

This PR changes our logic to limit when those calls are made, since none of them make sense to call when the VPN is connecting.

Sources/NetworkProtection/Status/ConnectionErrorObserver/ConnectionErrorObserverThroughSession.swift

@@ -88,7 +88,9 @@ public class ConnectionErrorObserverThroughSession: ConnectionErrorObserver {
 
     private func handleStatusChangeNotification(_ notification: Notification) {
         do {
-            guard let session = ConnectionSessionUtilities.session(from: notification) else {
+            guard let session = ConnectionSessionUtilities.session(from: notification),
+                session.status == .disconnected else {
+
                 return
             }
 

Sources/NetworkProtection/Status/ConnectionServerInfoObserver/ConnectionServerInfoObserverThroughSession.swift

@@ -98,6 +98,10 @@ public class ConnectionServerInfoObserverThroughSession: ConnectionServerInfoObs
     // MARK: - Obtaining the NetP VPN status
 
     private func updateServerInfo(session: NETunnelProviderSession) async {
+        guard session.status == .connected else {
+            return
+        }
+
         let serverAddress = await self.serverAddress(from: session)
         let serverLocation = await self.serverLocation(from: session)
 

Sources/NetworkProtection/Status/DataVolumeObserver/DataVolumeObserverThroughSession.swift

@@ -99,7 +99,9 @@ public class DataVolumeObserverThroughSession: DataVolumeObserver {
 
     private func updateDataVolume() {
         Task {
-            guard let session = await tunnelSessionProvider.activeSession() else {
+            guard let session = await tunnelSessionProvider.activeSession(),
+                session.status == .connected else {
+
                 return
             }