[Bug]: Join rows (cartesian product) hangs on Beam

### Apache Hop version?

2.3

### Java version?

11

### Operating system

Windows

### What happened?

Migration: https://issues.apache.org/jira/browse/HOP-4185

A pipeline containing a "Join rows (cartesian product)" transform with input from two sources loops forever when run via Beam-Direct or Dataflow. Attaching a debugger shows that it is stuck in the while loop at [JoinRows.java:486](https://github.com/apache/hop/blob/758c07c360c26c0447251f0a29df81557864ad11/plugins/transforms/joinrows/src/main/java/org/apache/hop/pipeline/transforms/joinrows/JoinRows.java#L487).

### Issue Priority

Priority: 3

### Issue Component

Component: Beam

Start with plugins/transforms/joinrows/src/main/java/org/apache/hop/pipeline/transforms/joinrows/JoinRows.java around line 486, and reproduce the pipeline with two input sources through Beam-Direct or Dataflow. Trace the while loop with the debugger and compare its behavior with the non-Beam execution. Done means the Join rows (cartesian product) transform completes instead of looping forever on Beam.

Written by the indexing model from the issue text.