Display scheduler errors in dagit
The startScheduledExecution mutation can return either StartPipelineExecutionSuccess or one of many errors (PipelineConfigValidationInvalid, PipelineNotFoundError, etc).
In the case that it's not StartPipelineExecutionSuccess, a run is not created, and users have to go into the scheduler debug logs to find the error. This diff adds a UI change in dagit that displays the error if the last entry in the scheduler debug logs was not StartPipelineExecutionSuccess
Test Plan: create pipeline stats_every_minute, introduce bug after couple runs, verify error is displayed
Reviewers: #ft, alangenfeld
Reviewed By: #ft, alangenfeld
Differential Revision: https://dagster.phacility.com/D1279