[helm] - error linting extraObjects in mimir-distributed.

[lasermoth]

Describe the bug

There is an error running helm lint when the extraObjects key is in use.

 [ERROR] templates/extra-manifests.yaml: unable to parse YAML: invalid Yaml document separator:

This does not cause a problem with helm template.

I'm not sure why lint and template behave differently when templating but the same issue is described here

This will be due to the leading - in the tpl functions introduced in 5.5.1 which is trimming the whitespace, causing it to join on the line with the yaml separator ---

To Reproduce

Steps to reproduce the behavior:

1. Run helm lint with mimir-distributed >= 5.5.1 with extraObjects: