feat: Mention vaadin.whitelisted-packages as a possible cause of missing template file

[tarekoraby]

Fixes #10120

[vaadin-bot]

SonarQube analysis reported 2 issues

1. LitTemplateParserImpl.java#L98: Reduce the total number of break and continue statements in this loop to use at most one.
2. NpmTemplateParser.java#L104: Reduce the total number of break and continue statements in this loop to use at most one.

[Haprog]

In a Spring Boot project, please ensure that the template's groupId is added to the vaadin.whitelisted-packages property.

Is this the case only if you're using vaadin.whitelisted-packages? If so the message should probably be adjusted to include that. Now it seems like you always need to add to vaadin.whitelisted-packages (even if you didn't use it before) in a Spring Boot project.

Just realized this after approving.

[tarekoraby]

Well, our starters from Vaadin starter come with the vaadin.whitelisted-packages property already preset. So the developer might not even know that such a property is activated on their project.

[vaadin-bot]

This ticket/PR has been released with platform 22.0.0.beta2 and is also targeting the upcoming stable 22.0.0 version.