KAlign error for too short sequences is not clear

Scenario to reproduce:

1. Open "_common_data/fasta/trim_fa.fa" as msa.
2. Align the msa with KAlign.
   Current state: the error it something like "Task {KAlign align 'trim_fa.fa'}

   finished with error: Subtask

   {Workflow wrapper 'KAlign align 'trim_fa.fa''}

   is failed: Subtask

   {Run workflow: align-kalign}

   is failed: Subtask

   {Read document: 'E91622.fasta'}

   is failed: Document is empty."

KAlign can't process sequences less then 6 bases.