add basic helm template sanitize and output in CI

[migmartri]

To avoid problems like this one https://github.com/chainloop-dev/chainloop/issues/1189 we should add some basic CI checks for the Helm Chart rendering.

What I'd do

• On PR, if the helm chart directory is touched
• do helm template chainloop -n chainloop . --set development=true
• ideally, show the diff compared to the version without the change

[migmartri]

cc/ @javirln