[Bug]: Do not run pipeline probe if you are running a source pipeline with a test pipeline.

### Apache Hop version?

2.18

### Java version?

21

### Operating system

Linux

### What happened?

For some reason, if I have a source pipeline running with a test pipeline where the test pipeline contains variables, it doesn't generate data for the probe pipeline.

### Issue Priority

Priority: 3

### Issue Component

Component: Transforms

No source files or tests are named. First reproduce the case on Apache Hop 2.18 with a source pipeline, a test pipeline containing variables, and the probe pipeline enabled; then trace the probe execution path for pipeline transforms. Done means the reported scenario behaves as intended and a regression test covers it.

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