upgrade go version to 1.24.8

lnd is currently using go 1.24.8 (https://github.com/lightningnetwork/lnd/blob/ab0177c1a10f0ef8227dc56eb44f25dc55716eed/go.mod#L219) and litd is currently using go 1.24.6 (https://github.com/lightninglabs/lightning-terminal/blob/d6b75578be9b034b612f8d67def9f830bc99c116/go.mod#L3) .

I can't compile litd master with lnd master because of this mismatch.