[Front-end-tools] Read Box bugs

[DOBEN]

Bug Description Using the readBox (third box from the top):

• Issue 1: Read functions with no input parameter return Error: Do not know how to serialize a BigInt. E.g. DECIMALS and requiredSignatures in contract instance 7283

• Issue 2: The [object Object] in the following error message should be fixed which appears when calling an entry point with e.g. the wrong input parameter.

Error: RPC call 'invokeContract' on method '[object Object].[object Object]' of contract '7283' failed. Reject reason: -2147483646.

Steps to Reproduce

• Issue 1: Use the readBox. Try to invoke DECIMALS and requiredSignatures in contract instance 7283.
• Issue 2: Use the readBox. Invoke an entry point with a wrong input parameter.

Expected Result

• Issue 1: Should work. No error message.
• Issue 2: No '[object Object].[object Object]' in error message.

Actual Result

• Issue 1: Error: Do not know how to serialize a BigInt. is returned.
• Issue 2: '[object Object].[object Object]' in error message.