Exception in cuebot if service icon is not present

[lithorus]

Describe the bug
If a layer is running using a custom service that does not have an icon on the cuebot server, it gets en exception that it's not able to read the image.

To Reproduce
Steps to reproduce the behavior:

1. Submit job with eg. the blender service
2. Wait for job to complete
3. See error in cuebot log

Expected behavior
Icons for custom services should be optional and not required. It should not bring an exception

Error Log

2024-07-22 21:43:15,990 ERROR pool-3-thread-1 com.imageworks.spcue.service.EmailSupport - Unable to read services/blender.png
java.io.IOException: Unable to load
	at com.imageworks.spcue.service.EmailSupport.loadImage(EmailSupport.java:101) [main/:?]
	at com.imageworks.spcue.service.EmailSupport.sendShutdownEmail(EmailSupport.java:263) [main/:?]
	at com.imageworks.spcue.service.JobManagerSupport.shutdownJob(JobManagerSupport.java:160) [main/:?]
	at com.imageworks.spcue.dispatcher.commands.DispatchJobComplete$1.wrapDispatchCommand(DispatchJobComplete.java:49) [main/:?]
	at com.imageworks.spcue.dispatcher.commands.DispatchCommandTemplate.execute(DispatchCommandTemplate.java:36) [main/:?]
	at com.imageworks.spcue.dispatcher.commands.DispatchJobComplete.run(DispatchJobComplete.java:51) [main/:?]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
	at java.lang.Thread.run(Thread.java:830) [?:?]

Version Number
688425c

Additional context
Seems related to the new email template when jobs are finished.