Describe the bug
PluginName is not set in FunctionInvokingContext and FunctionInvokedContext. Consequently, it is not possible to know the fully qualified name of the KernelFunction.

Additional context
The problem is that IFunctionFilter will often be used to tell the user when the chatbot is using a plugin, as it is done in ChatGPT.
For example, if the chatbot uses the HttpPlugin plugin, you need to be able to display "The agent is using the function HttpPlugin.GetAsync...", not "The agent is using the function GetAsync...".
It is therefore important that IFunctionFilter.OnFunctionInvoking() and IFunctionFilter.OnFunctionInvoked() provide the plugin name, not just the function name.