resolve: several follow-ups for 9ca133e97a0c8795b1f293ccea4965b4ad1accc4.

resolve: several follow-ups for 9ca133e97a0c8795b1f293ccea4965b4ad1accc4.

- add missing initialization for DnsQuery.answer_ede_rcode,

- clear EDE code and message in dns_transaction_reset_answer(),
  otherwise the previous EDE code or message may be mistakenly reused
  on restart. This fixes memory leak of DnsTransaction.answer_ede_msg.

- also clear EDE code and message in dns_query_reset_answer(),
  otherwise ede message is leaked if dns_query_accept() is called
  multiple times for the same DnsQuery.

Follow-up for 9ca133e97a0c8795b1f293ccea4965b4ad1accc4.

Fixes #30752.