Fix MultipleChooserPanel in nested InlinePanel

[elhussienalmasri]

Fixes #11233

the same issue exist in "ImageChooser" and most of the other widget like "SnippetChooser" and "DocumentChooser".
if this solution is suitable, other widgets could by solved by the same solution.

the other widgets not work but "MultipleChooserPanel" with "ImageChooser" widget in nested "InlinePanel" works, as shown below:

After	Before

[squash-labs]

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Test this branch here: https://elhussienalmasrifix-multiplech-lpq23.squash.io

[elhussienalmasri]

this issue could be solved without any modification , but just add outer "MultipleChooserPanel" with same widget as defined in the inner "MultipleChooserPanel" .if inner has "ImageChooser" just add like it in the outer. as shown below:

  class NestedPanels(Page):
    
    content_panels = Page.content_panels +  [
      InlinePanel("inner_MultipleChooserPanel"),
      # add outer  "MultipleChooserPanel" wih same widget.
      MultipleChooserPanel("outer_MultipleChooserPanel", chooser_field_name="image"),
    ]


  class SectionImage(Orderable):
    section = ParentalKey(NestedPanels, on_delete=models.CASCADE, related_name="outer_MultipleChooserPanel")
    image = models.ForeignKey("wagtailimages.Image", on_delete=models.CASCADE, related_name="+")

    panels = [
        FieldPanel("image"),
    ]