Describe the enhancement:

Improve error handling for the query submodule of Metricbeat's prometheus module: https://github.com/elastic/beats/blob/main/metricbeat/module/prometheus/query/query.go#L86

Describe a specific use case for the enhancement or feature:

When adding username, password, and SSL support to the query dataset (which is already implemented in the collector dataset) (see PR elastic/integrations#13969), the error messages in Metricbeat are ambiguous.
For example, when username or password is wrong, we have the following error messages:

For Collector (good and understandable):

For Query (obscure):