Output bindings not correctly supported when used with result processing triggers

[fabiocav]

Description

When using the .NET Worker in Azure Functions, there is an issue with how the output binding model works when the function is triggered by a result-processing trigger. Specifically, there is ambiguity around where the function’s result should be assigned. As a result, the wrong result may be mapped to the trigger or the output bindings.

We need this scenario to be correctly supported. There should be a clear mechanism to indicate how the binding result is processed so that the output bindings receive the intended data and the trigger does not receive invalid results.

Steps to reproduce

Use a result-processing trigger (e.g., McpToolTrigger) and a blob output binding.