refactor error handling part 1 (#307)

- created `getErrorMessage` function which takes in an error string or any type of error object and returns the correct error message
- replaced `error.message` with `getErrorMessage` since `error` could be a string in some cases
- merged sendNotificationForError.ts with ErrorHandlingUtils.ts
- some minor refactoring

In part 2, I will make the following changes:
 - Make `Logger.logError` function take an error message string instead of an error object. This will reduce some redundancy where the `getErrorMessage` function is being called twice (the error object passed by the caller is already an error message).
 - Update every `TelemetryProcessor.traceFailure` call to make sure we pass in an error message instead of an error object since we stringify the data we send.

src/Explorer/Panes/AddCollectionPane.ts

@@ -15,6 +15,7 @@ import { configContext, Platform } from "../../ConfigContext";
 import { ContextualPaneBase } from "./ContextualPaneBase";
 import { DynamicListItem } from "../Controls/DynamicList/DynamicListComponent";
 import { createCollection } from "../../Common/dataAccess/createCollection";
+import { getErrorMessage } from "../../Common/ErrorHandlingUtils";
 
 export interface AddCollectionPaneOptions extends ViewModels.PaneOptions {
   isPreferredApiTable: ko.Computed<boolean>;
@@ -881,10 +882,9 @@ export default class AddCollectionPane extends ContextualPaneBase {
         this.resetData();
         this.container.refreshAllDatabases();
       },
-      (reason: any) => {
+      (error: any) => {
         this.isExecuting(false);
-        const message = ErrorParserUtility.parse(reason);
-        const errorMessage = ErrorParserUtility.replaceKnownError(message[0].message);
+        const errorMessage: string = getErrorMessage(error);
         this.formErrors(errorMessage);
         this.formErrorsDetails(errorMessage);
         const addCollectionPaneFailedMessage = {
@@ -912,7 +912,7 @@ export default class AddCollectionPane extends ContextualPaneBase {
             flight: this.container.flight()
           },
           dataExplorerArea: Constants.Areas.ContextualPane,
-          error: reason
+          error: errorMessage
         };
         TelemetryProcessor.traceFailure(Action.CreateCollection, addCollectionPaneFailedMessage, startKey);
       }