fix(ci): grep the Zcash network correctly

[gustavovalverde]

Motivation

Some tests fail to grep Zcash network: ${{ inputs.network }}, and fail, timeout or take longer than needed.

Solution

• Use the same approach as in the Result of ${{ inputs.test_id }} test step, which is handling odd use cases nicely.

Review

• Validate the startup logs take less than 1-2 minutes

Reviewer Checklist

• Will the PR name make sense to users?
  • Does it need extra CHANGELOG info? (new features, breaking changes, large changes)
• Are the PR labels correct?
• Does the code do what the ticket and PR says?
  • Does it change concurrent code, unsafe code, or consensus rules?
• How do you know it works? Does it have tests?

[teor2345]

Thanks for this fix!