feat: clearer instructions for location of test results

[mihai-sysbio]

Main improvements in this PR:

This PR aims to clarify potential confusion regarding expecting the test results to be in this file, whereas they are provided as separate files in the current folder.

I hereby confirm that I have:

• Tested my code on my own computer for running the model
• Selected develop as a target branch
• Any removed reactions and metabolites have been moved to the corresponding deprecated identifier lists

[github-actions]

This PR has been automatically tested with GH Actions. Here is the output of the MACAW test:

Starting dead-end test...
 - Found 1382 dead-end metabolites.
 - Found 1138 reactions incapable of sustaining steady-state fluxes in either direction due to these dead-ends.
 - Found 1365 reversible reactions that can only carry steady-state fluxes in a single direction due to dead-ends.
Starting duplicate test...
 - Skipping redox duplicates because no redox_pairs and/or proton_ids were provided.
 - Found 379 reactions that were some type of duplicate:
   - 0 were completely identical to at least one other reaction.
   - 13 involve the same metabolites but go in the opposite direction or have the opposite reversibility as at least one other reaction.
   - 379 involve the same metabolites but with different coefficients as at least one other reaction.

This and a more detailed output from MACAW are also committed to data/macawResults/.

Note: In the case of multiple test runs, this post will be edited.

[JHL-452b]

LGTM!