remove as a preview feature (#3729)

Signed-off-by: Hannah Hunter <[email protected]>
Co-authored-by: Mark Fussell <[email protected]>

daprdocs/content/en/operations/support/support-preview-features.md

@@ -15,7 +15,6 @@ For CLI there is no explicit opt-in, just the version that this was first made a
 
 | Feature | Description | Setting | Documentation | Version introduced |
 | --- | --- | --- | --- | --- |
-| **App Middleware** | Allow middleware components to be executed when making service-to-service calls | N/A | [App Middleware]({{<ref "middleware.md#app-middleware" >}}) | v1.9 |
 | **Streaming for HTTP service invocation** | Enables (partial) support for using streams in HTTP service invocation; see below for more details. | `ServiceInvocationStreaming` | [Details]({{< ref "support-preview-features.md#streaming-for-http-service-invocation" >}}) | v1.10 |
 | **Pluggable components** | Allows creating self-hosted gRPC-based components written in any language that supports gRPC. The following component APIs are supported: State stores, Pub/sub, Bindings | N/A | [Pluggable components concept]({{<ref "components-concept#pluggable-components" >}})| v1.9  |
 | **Multi-App Run** | Configure multiple Dapr applications from a single configuration file and run from a single command | `dapr run -f` | [Multi-App Run]({{< ref multi-app-dapr-run.md >}}) | v1.10 |