Edge Functions are invoked with POST only

[niklasamslgruber]

Bug report

Describe the bug

The FunctionsClient invokes all edge functions using http method POST and ignores the http method provided in FunctionInvokeOptions. This was introduced in this PR FunctionInvokeOptions

To Reproduce

Try to invoke any edge function with:

client.functions
            .invoke(
                "delete_user",
                options: FunctionInvokeOptions(
                    method: .delete
                )
            )

and observe them failing if they only accept a certain http method such as DELETE. The underlying rawInvoke method initializes a new request with method = .post instead of respecting the provided method.

Expected behavior

Edge Functions should be triggered with the specified http method from the FunctionInvokeOptions