Wrong character encoding for UTF-8

[luprochazka-cen63872]

Function convert_json_to_string returns wrong encoding if you use UTF-8. I have workaround:

` @staticmethod
def convert_json_to_string(json_object):
"""Convert JSON object to string

    Arguments:
        - json_object: json as a dictionary object.

    Return new json_string

    Examples:
    | ${json_str}=  |  Convert JSON To String | ${json_obj} |
    """
    return json.dumps(json_object, **ensure_ascii=False**)`

[abelikt]

Hi,
indeed, for some reason we are getting Utf-16 instead of Utf-8 encoded data from json.dumps.
Like this German umlaut: json.dumps({"test":"über"}) results in '{"test": "\\u00fcber"}'.

Here is a test for this issue:

*** Settings ***
Library   JSONLibrary

*** Test Cases ***
Test_Conversion short
    ${data} =   Set Variable    "{'test':'über'}"
    ${json} =    Convert String To Json    ${data}
    ${string} =     Convert Json To String    ${json}
    # Issue: "{'test':'\u00fcber'}" != "{'test':'über'}"
    Should Be Equal    ${string}   ${data}

I created a PR here as a workaround to forward the ensure_ascii parameter to json.dumps:
#60

Regards,
Michael