`order_by_desc` not working with `cursor_by`

[samuelint]

Description

Using order_by_desc is not working with cursor_by.

Steps to Reproduce

// Returned values are `by_asc` even if `by_desc` is specified 
let result = thread::Entity::find()
    .cursor_by(thread::Column::Id)
    .order_by_desc(thread::Column::Id)
    .after(10)
    .before(0)
    .limit(10)
    .all(self.connection.as_ref())
    .await?;

// Not working either 
let result = thread::Entity::find()
    .order_by_desc(thread::Column::Id)
    .cursor_by(thread::Column::Id)
    .order_by_desc(thread::Column::Id)
    .after(10)
    .before(0)
    .limit(10)
    .all(self.connection.as_ref())
    .await?;

// This is working
let result = thread::Entity::find()
    .order_by_desc(thread::Column::Id)
    .all(self.connection.as_ref())
    .await?;

Expected Behavior

Data sorted by desc.

Actual Behavior

order_by_desc is not applied.

Reproduces How Often

100%

Workarounds

None for the moment

Reproducible Example

https://github.com/SeaQL/sea-orm/pull/2377

Versions

│   └── sea-orm-migration v0.12.15
│       ├── sea-orm v0.12.15
│       │   ├── sea-orm-macros v0.12.15 (proc-macro)
│       │   │   ├── sea-bae v0.2.0 (proc-macro)
│       │   ├── sea-query v0.30.7
│       │   │   ├── sea-query-derive v0.4.1 (proc-macro)
│       │   ├── sea-query-binder v0.5.0
│       │   │   ├── sea-query v0.30.7 (*)
│       ├── sea-orm-cli v0.12.15
│       │   ├── sea-schema v0.14.2
│       │   │   ├── sea-query v0.30.7 (*)
│       │   │   └── sea-schema-derive v0.2.0 (proc-macro)
│       ├── sea-schema v0.14.2 (*)
├── sea-orm v0.12.15 (*)

[Huliiiiii]

This is because we currently implement the Cursor as a cross-database polyfill. Although Cursor implements the QueryOrder trait, its methods are effectively no-ops. To apply ordering on a Cursor correctly, you should use Cursor::asc and Cursor::desc, but this only supports simple sorting based on all cursor-by columns and does not support complex sorting rules.