Unresponsive node bypasses timeout setting

[ok300]

Customer reported that calling sendPayment() returned only 5 minutes later with

"RpcError { code: None, message: \"no response from lightningd\",

Our Config::payment_timeout_sec

https://github.com/breez/breez-sdk/blob/77f0b65ba340767de6e290b1a579ea5baf044a16/libs/sdk-core/src/models.rs#L457

should have kicked it.

We should apply this timeout also as a connection timeout when calling GL methods.