Display the correct error message

Signed-off-by: Dominik Henneke <dominik.henneke@sda-se.com>

plugins/techdocs/src/client.test.ts

@@ -242,8 +242,8 @@ describe('TechDocsStorageClient', () => {
         .instances[0] as jest.Mocked<EventSource>;
 
       instance.onerror({
-        status: 500,
-        message: 'Some other error',
+        type: 'error',
+        data: 'Some other error',
       } as any);
 
       await expect(promise).rejects.toThrow(Error);

plugins/techdocs/src/client.ts

@@ -241,7 +241,7 @@ export class TechDocsStorageClient implements TechDocsStorageApi {
           // also handles the event-stream close. the reject is ignored if the Promise was already
           // resolved by a finish event.
           default:
-            reject(new Error(e.message));
+            reject(new Error(e.data));
             return;
         }
       };