audit_json.log serializes ip_address into JSON object

audit_json.log appears to be serializing ip_address as an object with family, addr, and mask_addr instead of just a simple string, which is causing Elasticsearch to reject these entries:

{   
   "severity":"INFO",
   "time":"2020-07-23T13:34:09.205Z",
   "correlation_id":"34IGPTSPB7",
   "id":null,
   "author_id":1954985,
   "entity_id":18869427,
   "entity_type":"Project",
   "details":{
      "author_name":"redacated",
      "target_id":310428,
      "target_type":"ApprovalProjectRule",
      "target_details":"anyone master",
      "custom_message":"Added User X to approval group on anyone master rule",
      "ip_address":null,
      "entity_path":"redacted"
   },
   "created_at":"2020-07-23T13:34:09.185Z",
   "ip_address":{
      "family":2,
      "addr":1300105045,
      "mask_addr":4294967295
   },
   "author_name":"redacted",
   "entity_path":"redacted",
   "target_details":null
}

@smcgivern @mwoolf I think this was partially fixed in !35356 (merged) (#224539 (closed)), but only in the presenter. If I look at the database entry, it seems we are storing an IPAddr object here? It seems to me we shouldn't do that?

[ gprd ] production> proj.audit_events.last
=> #<SecurityEvent id: 346169840, author_id: 1954985, type: "SecurityEvent", entity_id: 18869427, entity_type: "Project", details: {:author_name=>"Nadav", :target_id=>310429, :target_type=>"ApprovalProjectRule", :target_details=>"second eye", :custom_message=>"Added User X to approval group on second eye rule", :ip_address=>nil, :entity_path=>"redacted"}, created_at: "2020-07-23 13:34:09", ip_address: #<IPAddr: IPv4:77.126.7.85/255.255.255.255>, author_name: "edacted", entity_path: "redacted", target_details: nil>