Show the ingestion key update for LogDNA Target (IBM-Cloud#5953)

Co-authored-by: travis <travis>

Author: PhaniDivi-613

ibm/service/atracker/resource_ibm_atracker_target.go

@@ -93,11 +93,10 @@ func ResourceIBMAtrackerTarget() *schema.Resource {
 							Description: "The CRN of the LogDNA instance.",
 						},
 						"ingestion_key": {
-							Type:             schema.TypeString,
-							Required:         true,
-							Sensitive:        true,
-							DiffSuppressFunc: flex.ApplyOnce,
-							Description:      "The LogDNA ingestion key is used for routing logs to a specific LogDNA instance.",
+							Type:        schema.TypeString,
+							Required:    true,
+							Sensitive:   true,
+							Description: "The LogDNA ingestion key is used for routing logs to a specific LogDNA instance.",
 						},
 					},
 				},