Trampoline Interop: Final CLTV delta ignored

[carlaKC]

Ran into another small issue working on interop:
eclair -> eclair trampoline -> LDK recipient

(Claude tells me that) The test trampoline API ignored the min_final_cltv_expiry_delta, so payments to LDK fail: eclair sets 36, LDK wants a minimum of 42.

[t-bast]

This is fixed in #3353: thank you Claude for helping trampoline reach the finish line ;)