Modified EditForm to return _fixedEditContext via the EditContext parameter (#24007)

* Modified EditForm to return _fixedEditContext via the EditContext parameter. Also added some tests to cover the new functionality

* Swapped to boolean to track provided EditContext

* Patched ref assembly

* Simplified setting _hasSetEditContextExplicitly

* Renamed _fixedEditContext to _editContext

* Updated null check in OnParametersSet

* Simplified check for EditContext updates based on Model changes