Support actions being dispatched from multiple AccountUpdates

[MartinMinkov]

Description:

Fixes the format from fetched actions to support multiple account updates with events in the same transaction.

Addresses #798

Tested

All listed zkApp accounts have successful transactions. To test, two transactions were issued with varying AccountUpdates and actions emitted. Then a reduce was given, with success on Berkeley.

• zkApp emitting single action in a single Account Update:
  https://berkeley.minaexplorer.com/wallet/B62qp2R75kU97Sovki9987LNiDDcJkivRhPnpizvpzHWnhkXh3vqjt4
  [ [ '1' ], [ '1' ] ] -- getAction return value for two zkApp transactions with 1 Account Update each

• zkApp emitting two actions in a single AccountUpdate:
  https://berkeley.minaexplorer.com/wallet/B62qqNfTahass2YQfvgCs4L595gRnraadMGuK8bYsBK5VG2BdYEqhVw
  [ [ '1', '1' ], [ '1', '1' ] ] -- getAction return value for two zkApp transactions with 1 Account Update each

• zkApp emitting single action with 3 Account Updates in a single transaction
  https://berkeley.minaexplorer.com/wallet/B62qpYzTFqB7FcF79dyytvJ21jRUCxRespJVU2ZewV4CAEVAneop2BM
  [ [ '1' ], [ '1' ], [ '1' ], [ '1' ], [ '1' ], [ '1' ] ] -- getAction return value for two zkApp transactions with 3 Account Updates each

• zkApp emitting two actions in 3 AccountUpdates in a single transaction:
  https://berkeley.minaexplorer.com/wallet/B62qreiFZdVDNuXKVdujzJnqERfuxS5Wy4RQeNkJqhkjZCFibm25Qja
  [ [ '1', '1' ], [ '1', '1' ], [ '1', '1' ], [ '1', '1' ], [ '1', '1' ], [ '1', '1' ] ] -- getAction return value for two zkApp transactions with 3 Account Updates each

[Trivo25]

Just confirmed it works with a contract that didn't work yesterday, good job!

[mitschabaude]

Lgtm!