Views with transforms to not correctly handle related records

[AndrewSisley]

The Lens node does not fully convert the output of a Lens transform to a core.Doc - it only converts the top level document, this means that inner documents cannot properly have post-view stuff done to them (e.g. aggregates, filters, etc).

This has mostly been fixed in #2951 /2951-cached-views (not yet merged), however some problems remain caused by stuff not expecting schema only definitions (e.g. the sum node).

E.g. the below test will fail on the last action (failure depends on branch):

func TestView_OneToManyWithTransformOnOuterAndSum(t *testing.T) {
	test := testUtils.TestCase{
		Actions: []any{
			testUtils.SchemaUpdate{
				Schema: `
					type Author {
						name: String
						books: [Book]
					}
					type Book {
						name: String
						author: Author
						pages: Int
					}
				`,
			},
			testUtils.CreateView{
				Query: `
					Author {
						name
						books {
							name
						}
					}
				`,
				SDL: `
					type AuthorView @materialized(if: false) {
						fullName: String
						books: [BookView]
					}
					interface BookView {
						name: String
						pages: Int
					}
				`,
				Transform: immutable.Some(model.Lens{
					// This transform will copy the value from `name` into the `fullName` field,
					// like an overly-complicated alias
					Lenses: []model.LensModule{
						{
							Path: lenses.CopyModulePath,
							Arguments: map[string]any{
								"src": "name",
								"dst": "fullName",
							},
						},
					},
				}),
			},
			testUtils.CreateDoc{
				CollectionID: 0,
				Doc: `{
					"name":	"Ferdowsi"
				}`,
			},
			testUtils.CreateDoc{
				CollectionID: 1,
				DocMap: map[string]any{
					"name":   "Shahnameh",
					"author": testUtils.NewDocIndex(0, 0),
					"pages":  10,
				},
			},
			testUtils.Request{
				Request: `
					query {
						AuthorView {
							fullName
							_sum(books: {field: pages})
						}
					}
				`,
				Results: map[string]any{
					"AuthorView": []map[string]any{
						{
							"fullName": "Ferdowsi",
							"_sum":     10,
						},
					},
				},
			},
		},
	}

	testUtils.ExecuteTestCase(t, test)
}

Please do not pick this up until after #2951 is merged, as a lot of the problem has been solved and the code rewritten.