case reader bug and location bug

fixes https://github.com/participedia/usersnaps/issues/331 and similar issues -- result of a react-intl bug where we are passing a null value to the id, which throws this error:

the null value is a result of empty link entries for a case like this. ideally we would strip empty values on the backend, but until then this will fix the reader view.

fixes issue with showing location name twice https://github.com/participedia/usersnaps/issues/163 before:

after:

participedia / frontend

case reader bug and location bug #909