GraphQlClient: fix error handling

* Don't try to parse result if response-code is not 200
* Throw exception if not able to parse response.

Solves: Jira GER-1625
Change-Id: Ib7b3c226272e40abe24048577c008a599dadd3cc
1 file changed
tree: 93e650a2c4235ec5446b122b8329a3fbadb1377e
  1. src/
  2. BUILD
  3. external_plugin_deps.bzl