feat(core): stop realtime trigger and generate a FAILED execution if …

[loicmathieu]

…the publisher cannot be created

Part-of: #1256

Thanks to that, an error when creating the Publisher (so before receiving an event) will generate a failed executions and stop the trigger which will not be restarted except if the trigger is manually disabled/enabled.

There is multiple things to do to improve the behaviour:

• The log is not visible in the execution log tab itself but only in the flow logs page. This is a known issue, see #2521
• There is no way to restart a realtime trigger except disabling/re-enabling it in the YAML, we need a button for that in the trigger UI, I created https://github.com/kestra-io/kestra-ee/issues/1350 for that.

[loicmathieu]

The test is failing in develop, merging this.