Fix error handling in DE (#294)

- Replaced `JSON.stringify(error)` with `error.message`
- Created `ErrorHandlingUtils` and moved all error logging actions in there

src/Explorer/Graph/GraphExplorerComponent/GraphExplorer.tsx

@@ -892,7 +892,7 @@ export class GraphExplorer extends React.Component<GraphExplorerProps, GraphExpl
     backendPromise.then(
       (result: UserQueryResult) => (this.queryTotalRequestCharge = result.requestCharge),
       (error: any) => {
-        const errorMsg = `Failure in submitting query: ${query}: ${JSON.stringify(error)}`;
+        const errorMsg = `Failure in submitting query: ${query}: ${error.message}`;
         GraphExplorer.reportToConsole(ConsoleDataType.Error, errorMsg);
         this.setState({
           filterQueryError: errorMsg
@@ -1826,7 +1826,7 @@ export class GraphExplorer extends React.Component<GraphExplorerProps, GraphExpl
     promise
       .then((result: GremlinClient.GremlinRequestResult) => this.processGremlinQueryResults(result))
       .catch((error: any) => {
-        const errorMsg = `Failed to process query result: ${JSON.stringify(error)}`;
+        const errorMsg = `Failed to process query result: ${error.message}`;
         GraphExplorer.reportToConsole(ConsoleDataType.Error, errorMsg);
         this.setState({
           filterQueryError: errorMsg

src/Explorer/Graph/GraphExplorerComponent/GremlinClient.ts

@@ -57,9 +57,9 @@ export class GremlinClient {
           this.flushResult(result.requestId);
         }
       },
-      failureCallback: (result: Result, error: string) => {
+      failureCallback: (result: Result, error: any) => {
         if (typeof error !== "string") {
-          error = JSON.stringify(error);
+          error = error.message;
         }
 
         const requestId = result.requestId;