[Pcr, wd] Improve logging when using too small primers

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: an understandable error is displayed why the task cannot be completed.
   Current state: One of the given do not fits acceptable length. Task cancelled.
   What does this message refer to? If possible, indicate the error in the dashboard.

Check that the changes did not break the correct behavior in SV.