[Workflows] Missing `sendEvent` feature

The underlying `durabletask-java` library supports the feature for a Workflow to raise an event directly to another Workflow, via the [sendEvent](https://github.com/microsoft/durabletask-java/blob/0ef8a3a013803f52c0bf012adff7b3d5e09db6fc/client/src/main/java/com/microsoft/durabletask/TaskOrchestrationContext.java#L351) method.

The Dapr Workflows Java SDK has not implemented this method. [However the dotnet SDK has implemented it](https://github.com/dapr/dotnet-sdk/blob/03038fa519670b583eabcef1417eacd55c3e44c8/src/Dapr.Workflow/DaprWorkflowContext.cs#L68). For consistency across SDKs, I would recommend implementing this.