Fix class casting exception

[aegbert5]

Piezo-admin throws exceptions when trying to mark a one-time-trigger as complete, because it stores the trigger ID as a Long, but tries to read it as a String

piezo-admin[909417]: ERROR c.l.p.a.c.Triggers - Exception caught getting trigger DEFAULT MT_x6d66sqahyco. -- Identified object is not a String.                                                                                                    
piezo-admin[909417]: java.lang.ClassCastException: Identified object is not a String.                                                    
piezo-admin[909417]:         at org.quartz.utils.StringKeyDirtyFlagMap.getString(StringKeyDirtyFlagMap.java:384)                         
piezo-admin[909417]:         at com.lucidchart.piezo.admin.views.html.trigger$.apply$anonfun$3(trigger.template.scala:249)               
piezo-admin[909417]:         at scala.collection.ArrayOps$.map$extension(ArrayOps.scala:935)                                             
piezo-admin[909417]:         at com.lucidchart.piezo.admin.views.html.trigger$.apply(trigger.template.scala:251)                         
piezo-admin[909417]:         at com.lucidchart.piezo.admin.controllers.Triggers.getTrigger$anonfun$1(Triggers.scala:107)                 
piezo-admin[909417]:         at scala.Function1.$anonfun$andThen$1(Function1.scala:87)                                                   
piezo-admin[909417]:         at play.api.mvc.ActionBuilderImpl.invokeBlock(Action.scala:502)                                             
piezo-admin[909417]:         at play.api.mvc.ActionBuilderImpl.invokeBlock(Action.scala:502)                                             
piezo-admin[909417]:         at play.api.mvc.ActionBuilder$anon$10.apply(Action.scala:434)                                               
piezo-admin[909417]:         at play.api.mvc.Action.apply$anonfun$5(Action.scala:83)

Piezo-admin expects job-data-map values to always be stored as strings (otherwise loading the trigger page will fail), so we will store the id as a String instead of a Long