fix description for endTime in JobExecution (Azure#24359)

* fix description for endTime in JobExecution

* fix for breaking change error

Author: anandanthony

specification/app/resource-manager/Microsoft.App/preview/2023-05-02-preview/Jobs.json

@@ -814,8 +814,7 @@
           },
           "x-ms-client-flatten": true
         }
-      },
-      "required": []
+      }
     },
     "JobPatchProperties": {
       "type": "object",
@@ -1056,7 +1055,7 @@
           "type": "string"
         },
         "endTime": {
-          "description": "Job execution start time.",
+          "description": "Job execution end time.",
           "format": "date-time",
           "type": "string"
         },