test: update discovery to use custom version

[pablocarle]

Please check if your PR fulfills the following requirements. This is simply a reminder of what we are going to look for before merging your PR. If you don't know all of this information when you create this PR, don't worry. You can edit this template as you're working on it.

• Tests for the changes have been added (for bug fixes / features)
• Necessary documentation (if appropriate) have been added / updated
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• Bugfix
• Feature
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Does this PR introduce a breaking change?

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• No

Does this PR do something the person installing Zowe should know about?

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• Affected function: general area of interest *

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• Part: name of customizable file involved *

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multi-line description

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[github-actions]

build 6597 SUCCEEDED.
Link to workflow run: https://github.com/zowe/zowe-install-packaging/actions/runs/12314094669

[github-actions]

Test workflow 5807 is started.
Running install test: Convenience Pax
The zowe artifact being used by this test workflow: libs-snapshot-local/org/zowe/3.1.0-PR-4108/zowe-3.1.0-pr-4108-6597-20241213104234.pax
Running on machine: zzow09
Result: SUCCESS
Link to workflow run: https://github.com/zowe/zowe-install-packaging/actions/runs/12314168683