Revert "Pleroma.Web.AdminAPI.InstanceDocumentController: fix dialyzer error"

This reverts commit a3024dd5ac.

lib/pleroma/web/admin_api/controllers/instance_document_controller.ex

@@ -27,7 +27,7 @@ defmodule Pleroma.Web.AdminAPI.InstanceDocumentController do
     end
   end
 
-  def update(%{body_params: %{"file" => file}} = conn, %{name: document_name}) do
+  def update(%{body_params: %{file: file}} = conn, %{name: document_name}) do
     with {:ok, url} <- InstanceDocument.put(document_name, file.path) do
       json(conn, %{"url" => url})
     end

lib/pleroma/web/api_spec/operations/admin/instance_document_operation.ex

@@ -61,9 +61,9 @@ defmodule Pleroma.Web.ApiSpec.Admin.InstanceDocumentOperation do
       title: "UpdateRequest",
       description: "POST body for uploading the file",
       type: :object,
-      required: ["file"],
+      required: [:file],
       properties: %{
-        "file" => %Schema{
+        file: %Schema{
           type: :string,
           format: :binary,
           description: "The file to be uploaded, using multipart form data."