fix(subgraph_service): when the subgraph connection is closed or in error, return a proper subgraph response#5859

bnjjj merged 2 commits intodevapollographql/router:devfrom

bnjjj/fix_fatal_error_subgraph_resposneapollographql/router:bnjjj/fix_fatal_error_subgraph_resposneCopy head branch name to clipboard