Add a test to earlier detect issues like #22608, where a variable used in the configuration was not defined in the manifest.yml files of the filesets.

This could be reproduced by installing the pipelines of an specific module with filebeat setup --pipelines --modules aws.

It was not detected by current module tests because the configuration file using this variable is not used. The aws module uses by default the s3.yml configuration file, but it is tested with the file.yml configuration.

The new test should be able to check that all the included configurations for filesets can be resolved with the default settings.