fix: coverage for unknown network prop in marketplaces component

[patricio0312rev]

# [test] flaky marketplaces test

Summary

• Coverage for the default case in getNetworkName has been added.
• Now, the buttons will get # if the network is invalid. This will prevent the URLs from having missing props.
• A unit test has been added for these changes.

Checklist

• I checked my UI changes against the design and there are no notable differences
• I checked my UI changes for any responsiveness issues
• I checked my (code) changes for obvious issues, debug statements and commented code
• I opened a corresponding card on Clickup for any remaining TODOs in my code
• I added a short description on how to test this PR (if necessary)
• I added a storybook entry for the component that was added (if necessary)
• Documentation (if necessary)
• Tests (if necessary)
• Ready to be merged