Issue Summary

Exporting a plan in Bamboo as Java or YAML Specs fails with error > Can't find proper triggering repositories

Steps to Reproduce

1) Create a plan in Bamboo having 2 different linked Bitbucket repositories.
2) Under Branches Tab, go to Triggers section and choose a custom Trigger.
3) Choose "Bitbucket server repository trigerred" and choose anyone of the linked repositories and save it.
4) Go to the repositories tab of the plan and remove the repository which was chosen in step 3.
5) Try to Export the plan as YAML or Specs.

Expected Results

The plan configuration should get exported.

Actual Results

Internal server error is thrown, see attached

Stack Trace:

java.lang.IllegalStateException: Can't export trigger by id: 1. Can't find proper triggering repositories: [7077891]
	at com.atlassian.bamboo.configuration.external.helpers.TriggerDefinitionExportHelper.lambda$toSpecsEntity$0(TriggerDefinitionExportHelper.java:102)
	at java.base/java.util.stream.ReferencePipeline$11$1.accept(ReferencePipeline.java:441)

Workaround

Modify the Custom Trigger in the Branches tab and revert it back to None and try to export the plan, it should work. You can later set the custom trigger.