Map object | MapContent object | update_layer() method not working in 2.4.3

[Clubdebambos]

Describe the bug
In 2.4.2 the Map object, MapContent object, update_layer() worked just fine. In 2.4.3, the same workflows fail to run.

The layer is not a group layer or a layer in a group.

To Reproduce
Steps to reproduce the behavior:

from arcgis.gis import GIS
from arcgis.map import Map

agol = GIS("home")

wm_item = agol.content.get("WM_ITEM_ID")

webmap = Map(wm_item)

options_dict = {
    "title" : "National Inventory of Architectural Heritage (NIAH)"
}

## fails here
webmap.content.update_layer(
    index=0,
    options=options_dict
)

webmap.update()

error:

Traceback (most recent call last):
  File "C:\ArcGISAFP_03\Python_Scripts\Completed\07_Layer_Settings\rename_layer.py", line 61, in <module>
    webmap.content.update_layer(
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        index=lyr_index,
        ^^^^^^^^^^^^^^^^
        options=options_dict
        ^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\map\map_widget.py", line 2230, in update_layer
    self._helper.update_layer(
    ~~~~~~~~~~~~~~~~~~~~~~~~~^
        index,
        ^^^^^^
    ...<5 lines>...
        form,
        ^^^^^
    )
    ^
  File "C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\arcgis\map\_utils.py", line 1972, in update_layer
    if isinstance(layer, group_layer.BaseGroup):
                         ^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'bool' object has no attribute 'BaseGroup'

Screenshots
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Expected behavior
The above is simply attempting to rename a layer. Worked perfect in 2.4.2 and fails in 2.4.3

Platform (please complete the following information):

• OS: Windows 11
• Browser: Chrome / Edge
• Python API Version: 2.4.3

Additional context
Add any other context about the problem here, attachments etc.

[nanaeaubry]

@Clubdebambos We are really sorry you have run into this and this should have been caught during certification.

I have provided a workaround below but please be aware this uses a private property to access the underlying map structure we are working with.
We will work on fixing this for the next release and building out better certification testing for the update layer method.

from arcgis.gis import GIS
from arcgis.map import Map

agol = GIS("home")

wm_item = agol.content.get("WM_ITEM_ID")

webmap = Map(wm_item)

webmap._webmap.operational_layers[0].title = "National Inventory of Architectural Heritage (NIAH)"

webmap._update_source()

webmap.update()

cc @ManushiM @jyaistMap