fix doubling search results in Search Result Panel

After fix local search in SFC POU in 163d3a8, search results tree assemble with "children" branches: results of search in actions anf transitions. Deleted code doubling this search results into one more separate branch, so it's useless.

Beremiz's user manual
=====================

Contents:

.. toctree::
   :maxdepth: 2

   install
   start
   edit
   build
   connectors
   debug