chore: replace PPRemoveAbsolutePaths with generic fixture template data

[pd93]

Followup to the style of test that was added in #2256. Instead of expecting a struct of type any, I have converted it to use a map[string]any. This largely works the same way, but with the benefit that defining variables is a bit nicer syntactically and we can utilise functions like maps.Copy() to do key merging. This allows us to define a predefined set of variables for use in all tests and then merge additional values if required.

Variables being made available for now are:

• TEST_NAME - Contains the name of the test
• TEST_DIR - Contains the absolute path to the test directory

I have removed PPRemoveAbsolutePaths in favor of this new technique.

One small hiccup is that since #2256 was merged, running task gen:fixtures will remove the template values from the golden files which then causes the tests to fail. This can be resolved manually, but is a bit of a pain. This is reported in sebdah/goldie#14 and I am considering an upstream feature request if @sebdah is interested. have opened a PR to address it.

[sebdah]

This is a good idea. I'd be happy to merge this into goldie if you'd want to submit a PR.