OpenAPI: Remove max pagination limit from the spec

In an ideal world clients wouldn't try to request more than the max
hardcoded limit, but SubwayTooter does.

lib/pleroma/web/api_spec/helpers.ex

@@ -41,8 +41,8 @@ def pagination_params do
       Operation.parameter(
         :limit,
         :query,
-        %Schema{type: :integer, default: 20, maximum: 40},
-        "Limit"
+        %Schema{type: :integer, default: 20},
+        "Maximum number of items to return. Will be ignored if it's more than 40"
       )
     ]
   end