Currently when a toolgroup doesn't contain the same amount of tools between all modes an error can occur:
```
Traceback (most recent call last):
File "/home/david/blender-git/build_linux_lite/bin/2.83/scripts/startup/bl_operators/wm.py", line 1687, in execute
if fn(context, space_type, self.name, as_fallback=self.as_fallback):
File "/home/david/blender-git/build_linux_lite/bin/2.83/scripts/startup/bl_ui/space_toolsystem_common.py", line 994, in activate_by_id
_activate_by_item(context, space_type, item, index, as_fallback=as_fallback)
File "/home/david/blender-git/build_linux_lite/bin/2.83/scripts/startup/bl_ui/space_toolsystem_common.py", line 956, in _activate_by_item
item_fallback, _index = cls._tool_get_active_by_index(context, select_index)
File "/home/david/blender-git/build_linux_lite/bin/2.83/scripts/startup/bl_ui/space_toolsystem_common.py", line 394, in _tool_get_active_by_index
item = item[index]
IndexError: tuple index out of range
```
Steps to reproduce:
-start blender with default settings
-in the texteditor open following script:
{F8474566}
-run the script
-in the 3dview activate the newly registered tool 'My Circle Select' (last tool in the first tool-group)
-switch to editmode while 'My Circle Select' is the active tool
-error should appear