disconnected: removes deprecated disconnect fields (#25284)

The group level fields stop_after_client_disconnect,
max_client_disconnect, and prevent_reschedule_on_lost were deprecated in
Nomad 1.8 and replaced by field in the disconnect block. This change
removes any logic related to those deprecated fields.

---------

Co-authored-by: Tim Gross <tgross@hashicorp.com>

command/agent/job_endpoint.go

@@ -1249,24 +1249,10 @@ func ApiTgToStructsTG(job *structs.Job, taskGroup *api.TaskGroup, tg *structs.Ta
 		RenderTemplates: *taskGroup.RestartPolicy.RenderTemplates,
 	}
 
-	if taskGroup.PreventRescheduleOnLost == nil {
-		tg.PreventRescheduleOnLost = false
-	} else {
-		tg.PreventRescheduleOnLost = *taskGroup.PreventRescheduleOnLost
-	}
-
 	if taskGroup.ShutdownDelay != nil {
 		tg.ShutdownDelay = taskGroup.ShutdownDelay
 	}
 
-	if taskGroup.StopAfterClientDisconnect != nil {
-		tg.StopAfterClientDisconnect = taskGroup.StopAfterClientDisconnect
-	}
-
-	if taskGroup.MaxClientDisconnect != nil {
-		tg.MaxClientDisconnect = taskGroup.MaxClientDisconnect
-	}
-
 	if taskGroup.ReschedulePolicy != nil {
 		tg.ReschedulePolicy = &structs.ReschedulePolicy{
 			Attempts:      *taskGroup.ReschedulePolicy.Attempts,

command/agent/job_endpoint_test.go

@@ -2800,7 +2800,6 @@ func TestJobs_ApiJobToStructsJob(t *testing.T) {
 				Disconnect: &api.DisconnectStrategy{
 					LostAfter: pointer.Of(30 * time.Second),
 				},
-				MaxClientDisconnect: pointer.Of(30 * time.Second),
 				Tasks: []*api.Task{
 					{
 						Name:   "task1",
@@ -3113,7 +3112,6 @@ func TestJobs_ApiJobToStructsJob(t *testing.T) {
 						Operand: "z",
 					},
 				},
-				PreventRescheduleOnLost: false,
 				Affinities: []*structs.Affinity{
 					{
 						LTarget: "x",
@@ -3248,7 +3246,6 @@ func TestJobs_ApiJobToStructsJob(t *testing.T) {
 					Replace:   pointer.Of(true),
 					Reconcile: structs.ReconcileOptionBestScore,
 				},
-				MaxClientDisconnect: pointer.Of(30 * time.Second),
 				Tasks: []*structs.Task{
 					{
 						Name:   "task1",
@@ -3625,9 +3622,8 @@ func TestJobs_ApiJobToStructsJob(t *testing.T) {
 		},
 		TaskGroups: []*structs.TaskGroup{
 			{
-				Name:                    "group1",
-				Count:                   5,
-				PreventRescheduleOnLost: false,
+				Name:  "group1",
+				Count: 5,
 				Constraints: []*structs.Constraint{
 					{
 						LTarget: "x",