[client] Android - Serialize Android tunnel reconfiguration callbacks (#6990)

## Describe your changes

The Android route notifier and the DNS search-domain notifier both
delivered OnNetworkChanged from a fire-and-forget goroutine per update.
Two updates in quick succession could reach the Java side reordered: the
TUN rebuild handler applies them in arrival order and compares against
the last applied parameters, so a stale route set delivered last won as
the final TUN state. This is the same reordering hazard fixed for iOS in
#6454.

Wrap the Android network change listener into the shared tunnelnotifier
FIFO introduced in #6870, the same way RunOniOS does, and deliver both
notifiers synchronously into it. Enqueueing is non-blocking, a single
delivery goroutine preserves order, and calls into Java never overlap.

Also stop hasRouteDiff from sorting the notifier's shared route slices
in place; compare sorted copies instead.

## Issue ticket number and link

## Stack

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### Checklist
- [x] Is it a bug fix
- [ ] Is a typo/documentation fix
- [ ] Is a feature enhancement
- [ ] It is a refactor
- [ ] Created tests that fail without the change (if possible)
- [ ] This change does **not** modify the public API, gRPC protocols,
functionality behavior, CLI / service flags, or introduce a new feature
— **OR** I have discussed it with the NetBird team beforehand (link the
issue / Slack thread in the description). See
[CONTRIBUTING.md](https://github.com/netbirdio/netbird/blob/main/CONTRIBUTING.md#discuss-changes-with-the-netbird-team-first).

> By submitting this pull request, you confirm that you have read and
agree to the terms of the [Contributor License
Agreement](https://github.com/netbirdio/netbird/blob/main/CONTRIBUTOR_LICENSE_AGREEMENT.md).

## Documentation
Select exactly one:

- [ ] I added/updated documentation for this change
- [x] Documentation is **not needed** for this change (explain why)

### Docs PR URL (required if "docs added" is checked)
Paste the PR link from https://github.com/netbirdio/docs here:

https://github.com/netbirdio/docs/pull/__

client/internal/connect.go

@@ -113,11 +113,14 @@ func (c *ConnectClient) RunOnAndroid(
 	stateFilePath string,
 	cacheDir string,
 ) error {
+	notifier := tunnelnotifier.New(networkChangeListener, nil)
+	defer notifier.Close()
+
 	// in case of non Android os these variables will be nil
 	mobileDependency := MobileDependency{
 		TunAdapter:            tunAdapter,
 		IFaceDiscover:         iFaceDiscover,
-		NetworkChangeListener: networkChangeListener,
+		NetworkChangeListener: notifier,
 		HostDNSAddresses:      dnsAddresses,
 		DnsReadyListener:      dnsReadyListener,
 		StateFilePath:         stateFilePath,

client/internal/dns/notifier.go

@@ -51,7 +51,5 @@ func (n *notifier) notify() {
 		return
 	}
 
-	go func(l listener.NetworkChangeListener) {
-		l.OnNetworkChanged("")
-	}(n.listener)
+	n.listener.OnNetworkChanged("")
 }

client/internal/routemanager/notifier/notifier_android.go

@@ -79,9 +79,7 @@ func (n *Notifier) notify() {
 
 	routeStrings := n.routesToStrings(allRoutes)
 	sort.Strings(routeStrings)
-	go func(l listener.NetworkChangeListener) {
-		l.OnNetworkChanged(strings.Join(routeStrings, ","))
-	}(n.listener)
+	n.listener.OnNetworkChanged(strings.Join(routeStrings, ","))
 }
 
 func filterStatic(routes []*route.Route) []*route.Route {
@@ -103,16 +101,11 @@ func (n *Notifier) routesToStrings(routes []*route.Route) []string {
 }
 
 func (n *Notifier) hasRouteDiff(a []*route.Route, b []*route.Route) bool {
-	slices.SortFunc(a, func(x, y *route.Route) int {
-		return strings.Compare(x.NetString(), y.NetString())
-	})
-	slices.SortFunc(b, func(x, y *route.Route) int {
-		return strings.Compare(x.NetString(), y.NetString())
-	})
-
-	return !slices.EqualFunc(a, b, func(x, y *route.Route) bool {
-		return x.NetString() == y.NetString()
-	})
+	as := n.routesToStrings(a)
+	bs := n.routesToStrings(b)
+	sort.Strings(as)
+	sort.Strings(bs)
+	return !slices.Equal(as, bs)
 }
 
 func (n *Notifier) GetInitialRouteRanges() []string {