After doc deletion the doc can still be fetched from another collection

[islamaliev]

This test does not pass:

func TestMutationDeletion_WithMultipleCollections_(t *testing.T) {
	test := testUtils.TestCase{
		Description: "Delete a document from one collection and check if the other collection is unaffected.",
		Actions: []any{
			testUtils.SchemaUpdate{
				Schema: `
					type User {
						name: String
					}
					type Pet {
						name: String
						breed: [String]
					}
				`,
			},
			testUtils.CreateDoc{
				Doc: `{
					"name": "Shahzad"
				}`,
			},
			testUtils.CreateDoc{
				Doc: `{
					"name": "John"
				}`,
			},
			testUtils.CreateDoc{
				CollectionID: 1,
				Doc: `{
					"name": "Scruffy",
					"breed": ["Yorkie"]
				}`,
			},
			testUtils.DeleteDoc{
				CollectionID: 1,
				DocID:        0,
			},
			testUtils.Request{
				Request: `query {
					Pet {
						_docID
					}
				}`,
				Results: map[string]any{
					"Pet": []map[string]any{},
				},
			},
			testUtils.Request{
				Request: `query {
					User {
						_docID
					}
				}`,
				Results: map[string]any{
					"User": []map[string]any{
						{
							"_docID": testUtils.NewDocIndex(0, 1),
						},
						{
							"_docID": testUtils.NewDocIndex(0, 0),
						},
					},
				},
			},
		},
	}

	testUtils.ExecuteTestCase(t, test)
}

The last query returns 3 documents.