add ResourceDestroyed and revert schedule to access(all)

Author: joshuahannan

contracts/FlowCallbackScheduler.cdc

@@ -164,6 +164,9 @@ access(all) contract FlowCallbackScheduler {
             self.id = id
             self.timestamp = timestamp
         }
+
+        // event emitted when the resource is destroyed
+        access(all) event ResourceDestroyed(id: UInt64 = self.id, timestamp: UFix64 = self.timestamp)
     }
 
     /// Estimated callback contains data for estimating callback scheduling.
@@ -1350,7 +1353,7 @@ access(all) contract FlowCallbackScheduler {
         return <-vaultRef.withdraw(amount: amount) as! @FlowToken.Vault
     }
 
-    access(account) fun schedule(
+    access(all) fun schedule(
         callback: Capability<auth(Execute) &{CallbackHandler}>,
         data: AnyStruct?,
         timestamp: UFix64,