Add new logic to validate kv-pair

:Release Notes:
Add new logic to validate kv-pair

:Detailed Notes:
Add logic to validate if includes "} "
(closing curly brace and whitespace) in kv-pair string.

:Testing Performed:
Compiled locally and tested on a device.

:QA Notes:

:Issues Addressed:
[GF-52565] Providing insert json object string into key-value pair

Open-webOS-DCO-1.0-Signed-off-by: Hongjeon Ha <hj.ha@lge.com>

Change-Id: Ib42f96592b54c4dd5198e499171032e67b4dbed0
Reviewed-on: https://g2g.palm.com/4032
Reviewed-by: DCO Verification
Reviewed-by: Hongjeon Ha <hj.ha@lge.com>
Tested-by: Hongjeon Ha <hj.ha@lge.com>
Reviewed-by: Gayathri Srinivasan <gayathri.srinivasan@lge.com>