Ensure coverage with tests of all workflow configurations

[ekatef]

It appears that some configuration of the workflow are not captured by CI.

For example, recent bugs in augmented_line_connections have been obvious with run_tests but were not found by CI, as reported by @finozzifa when working on #1011 and #1013.

Currently augmentation is not used in the tutorial:

pypsa-earth/config.tutorial.yaml

Lines 63 to 64 in 3f3a32f

	augmented_line_connection:
	add_to_snakefile: false # If True, includes this rule to the workflow

But it's switched-on in custom.config which should be used to build a test configuration:

pypsa-earth/test/config.custom.yaml

Lines 19 to 20 in 3f3a32f

	augmented_line_connection:
	add_to_snakefile: true # If True, includes this rule to the workflow

Describe the feature you'd like to see

Would be great to ensure that CI runs all the rules.

[ekatef]

As a comment, it would be also great to use both AC and DC representations in CI tests. Although, DC part is a bit tricky as it requires adding new data to the tutorial.

[ekatef]

We still have a number of testing related issues which may be related to this one. In particular,
#625 and #715 can be relevant.

[ekatef]

Is linked with #1174

[davide-f]

Also linked to #1203