[5.3] Added Exception Message to Taks Notification Email

[brbrbr]

Summary of Changes

The email sent by the system plugin task notification contains very little useful information. This adjustment adds the Exception message to the emails.
The emails point to the Joomla! backend for more information, however there is no info in the dashboard since the taskcontent is not stored and the logs are well hidden.

Testing Instructions

Enable email notifications for failure for any active task for example in sessiongc. Is enabled by default.

Throw an exception in that task, for example:
` private function sessionGC(ExecuteTaskEvent $event): int
{

    throw new \Exception('test');

...
`
execute the task

Actual result BEFORE applying this Pull Request

Email with little information

Expected result AFTER applying this Pull Request

Email with the exception message

Link to documentations

Please select:

• Documentation link for docs.joomla.org:

• No documentation changes for docs.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed

[brianteeman]

If the email now includes the message is there any point in telling someone to go to the joomla admin etc?

[brbrbr]

If the email now includes the message is there any point in telling someone to go to the joomla admin etc?

Good point,

Actually, in the current situation, there is also no point of telling someone to go to the admin. Since there is no information there.
(unless you have an extension to view the logs).

Should I include the debug trace in the email as well? That one is neither stored nor logged.

Bram

[LadySolveig]

Thank you @brbrbr for your work!
I've rebased this PR to 5.2 as an improvement. 5.1 only gets bugfixes.

[HLeithner]

This pull request has been automatically rebased to 5.3-dev.