JSON-RPC spec: fixed the data type of event.sequence_number
JSON-RPC spec: fixed the data type of event.sequence_number

The `sequence_number` property of the transaction event object has been erroneously specified as string. Changed to unsigned int64.

Closes: #5836

aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,libra/libra,libra/libra,aptos-labs/aptos-core,libra/libra,libra/libra,aptos-labs/aptos-core