Avoid NPE sending email on dev machines

[labkey-jeckels]

Rationale

Every morning I find a message like this in my dev server's logs:

ERROR ErrorLogger              2024-08-23T08:04:55,932 uartzScheduler_Worker-10 : Job (TestResultsGroup.TestResultsEmailTrigger threw an exception.
org.quartz.SchedulerException: Job threw an unhandled exception.
	at org.quartz.core.JobRunShell.run(JobRunShell.java:213) [quartz-2.3.2.jar:?]
	at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573) [quartz-2.3.2.jar:?]
Caused by: java.lang.NullPointerException: Cannot invoke "org.labkey.api.security.User.getEmail()" because "from" is null
	at org.labkey.testresults.SendTestResultsEmail.execute(SendTestResultsEmail.java:330) ~[testresults-24.9-SNAPSHOT.jar:?]
	at org.labkey.testresults.SendTestResultsEmail.execute(SendTestResultsEmail.java:347) ~[testresults-24.9-SNAPSHOT.jar:?]
	at org.quartz.core.JobRunShell.run(JobRunShell.java:202) ~[quartz-2.3.2.jar:?]
	... 1 more

It's because I don't have a user account that the code assumes will be available.

Changes

• Simple null check to ensure the user exists before attempting to send email

[vagisha]

Thanks!