fix: run the 'post' stage of the service always

For most of the Talos service `post` stage does nothing, so it was never
properly noticed. FOr extension service, pre/post stages perform
mounting and unmounting of the overlayfs, so if post stage doesn't run
(if the runner can't be created), next time service is started, it won't
start as the post stage never ran.

Signed-off-by: Andrey Smirnov <andrey.smirnov@talos-systems.com>

internal/app/machined/pkg/system/service_runner.go

@@ -239,6 +239,15 @@ func (svcrunner *ServiceRunner) Start() {
 		return
 	}
 
+	defer func() {
+		// PostFunc passes in the state so that we can take actions that depend on the outcome of the run
+		state := svcrunner.GetState()
+
+		if err := svcrunner.service.PostFunc(svcrunner.runtime, state); err != nil {
+			svcrunner.UpdateState(events.StateFailed, "Failed to run post stage: %v", err)
+		}
+	}()
+
 	if runnr == nil {
 		svcrunner.UpdateState(events.StateSkipped, "Service skipped")
 
@@ -250,15 +259,6 @@ func (svcrunner *ServiceRunner) Start() {
 	} else {
 		svcrunner.UpdateState(events.StateFinished, "Service finished successfully")
 	}
-
-	// PostFunc passes in the state so that we can take actions that depend on the outcome of the run
-	state := svcrunner.GetState()
-
-	if err := svcrunner.service.PostFunc(svcrunner.runtime, state); err != nil {
-		svcrunner.UpdateState(events.StateFailed, "Failed to run post stage: %v", err)
-
-		return
-	}
 }
 
 //nolint:gocyclo