[BUG] Selection Face By Index For Extrude is always changing

**Describe the bug**
I am trying to make simple extrusion that relies on Index Selection, for face, somewhat when I make changes to the extrude, the index changes. It's very tricky to get right.

**To Reproduce**

Create Cube
Select Face By Index
Extrude
Select Another Face By Index
Extrude
Make changes to Extrude value
Suddenly Extruded area is changing --- NOTE: This does not seem to always happen however I did experience this issue in my video below.

**Expected behavior**
I wish for index not changing much. Is this limitation?

**Screenshots**

**Desktop (please complete the following information):**
- OS: Mac OS Cataline 10.15.6 Beta (19G36e)
- Blender Version 2.83
- Sorcar Version 3.20

**Additional context**
VIDEO: around 5 minutes
https://youtu.be/ig58KHxI81U

The issue involves face index selection and extrusion in a Blender add-on. Look at the Sorcar node editor code, likely in the extrusion node logic. The video shows the bug in action. Start by reproducing the issue in Blender with Sorcar installed, then examine how face indices are stored and updated during extrusion operations. Check for any existing tests related to selection or extrusion.

Escrita pelo modelo de indexação a partir do texto da issue.