Merge "Since we are using string.subString(startIndex, endIndex) when parsing...

Merge "Since we are using string.subString(startIndex, endIndex) when parsing denylist, we should make sure startIndex <= endIndex before calling string.substring(). Otherwise, an index out of bound excpetion would throw and make the app terminate. This could happen if we are not careful with the denylist and make the denylist wrong formatted. For example, a ";" is left out in the end, and startIndex in this case would become -1." into udc-dev