fix: simplify jwk assignment in migration_key resource

Author: VarunAthreya

tests/migration/fixtures/gateway.tf

@@ -360,15 +360,7 @@ resource "konnect_gateway_key_set" "migration_key_set" {
 resource "konnect_gateway_key" "migration_key" {
   kid  = "migration-kid-1"
   name = "migration-key"
-  jwk = jsonencode({
-    kty = "RSA"
-    kid = "migration-kid-1"
-    use = "sig"
-    alg = "RS256"
-    e   = "AQAB"
-    n   = "tk5VuZUPrDvdDgS_Fouj2q1PXWyuYC0vEdKE6uZVrUrsoJlBAQZXNiMt3YtBvBUjXOEtRCXn7giRbHfqPxTFvNwKsiCIJZC7rsN6OCeQgC2hbiE77yAQtlWk_mWwvcVrg1Xo-ZcoxG592iJo9dTKRqpVmEWePNqIbUXJH4s3jjyPdkTqgfY9NZrBezilnAGgRlvDKJIye6iOqpw4KFqYaWcoiBTfgnTYhKGbhPrPRDFhspEfu6deTx069i84exMcExiaGRM-Bco7WfemnstkwGfi4u5jrVCQBg7r7TaBv37I4DY7uqOoWv1swobhM2Jk3vGRoLEZTiiIjPkTb2ZH6Q"
-  })
-
+  jwk = {"kty":"RSA","kid":"migration-kid-1","use":"sig","alg":"RS256","e":"AQAB","n":"tk5VuZUPrDvdDgS_Fouj2q1PXWyuYC0vEdKE6uZVrUrsoJlBAQZXNiMt3YtBvBUjXOEtRCXn7giRbHfqPxTFvNwKsiCIJZC7rsN6OCeQgC2hbiE77yAQtlWk_mWwvcVrg1Xo-ZcoxG592iJo9dTKRqpVmEWePNqIbUXJH4s3jjyPdkTqgfY9NZrBezilnAGgRlvDKJIye6iOqpw4KFqYaWcoiBTfgnTYhKGbhPrPRDFhspEfu6deTx069i84exMcExiaGRM-Bco7WfemnstkwGfi4u5jrVCQBg7r7TaBv37I4DY7uqOoWv1swobhM2Jk3vGRoLEZTiiIjPkTb2ZH6Q"}
   set = {
     id = konnect_gateway_key_set.migration_key_set.id
   }