Fix the case count in the "gen-interop.sh" script

[swcurran]

Something has changed in the Allure interface such that the number of cases coming back from the calls is incorrect -- higher than it should be. Not sure of the cause of the issue -- investigating. Example:

File: .github/workflows/test-harness-acapy-aip10.yml
PASSED: 35 /TOTAL_CASES: 161 =PERCENT: 21

The total cases should be 35, showing, along with all of the other ACA-Py tests, 161. As a result, the percentages are way off.