Option to set the `json: false` flag on `get_table_rows` back to `true`

[aaroncox]

For debugging and maybe specific use cases, it would be good if the json flag on the table query could be set back to true.

Right now its hardcoded in two places to false.

contract/src/contract/table.ts

Line 148 in 405bee1

json: false,

contract/src/contract/table-cursor.ts

Line 111 in 405bee1

json: false,