[Pcr, crash] Cancel PCR workflow

1. Open WD.
2. Switch to Samples, double click on the "In silico PCR" schema.
   Expected: the "In Silico PCR" wizard appears.
3. Select _common_data/fasta/chr6.fa as input and click Next.
4. Select the attached file as Primers and click Next.
5. Finally, click Run.
   Expected: the workflow started.
6. Wait until the progress reaches 90% or 93% (see progress in the Dashboard) then click "Stop workflow").
   Expected: the workflow stopped successfully.
   Current state: crash.

Restart the workflow if there is no crash.