use-of-uninitialized-value in rdata seek

use-of-uninitialized-value in rdata seek: a task in MiMo-V2.6-RL-oss: Agentic RL Environments (MiMo RL release). MemorySanitizer: use-of-uninitialized-value in function rdata seek in file knot-dns/src/libknot/rrtype/tsig.c