Blender Git Loki

Fix text object inserting multiple characters with a selection

`bpy.ops.font.text_insert(text="multiple characters")` wasn't working.

When the text is selected does not correctly insert multiple characters.

- When the text was selected from left to right,
the cursor only move one position next to the selected text.
- When the text is selected from right to left,
a part of the selected text remain.

Ref D12161