API: Healthcheck Output field delay

#### Overview of the Issue

There's a ~7 min delay in showing the service health check output in the UI. When registering a service with a failing healthcheck, when I look at the Consul UI, I see the Output field as blank for 7 min before it gets populated with the failure. When I `curl localhost:8500/v1/agent/checks`, I see the Output error message without delay, so I'd expect to see it sooner in the UI.

May be related issue: https://github.com/hashicorp/consul/issues/8225

#### Reproduction Steps

Steps to reproduce this issue, eg:

1. Clone this repo and `make dev` to put binary in GOPATH
1. `consul agent -dev`
1. Open the UI in a browser tab `http://localhost:8500/ui/dc1/services`
1. Create payload.json with the service and healthcheck to register. (The healthcheck will fail since nothing is listening on port 8888):

payload.json

```
{
"ID": "redis1",
"Name": "redis",
"Tags": [
"primary",
"v1"
],
"Address": "127.0.0.1",
"TaggedAddresses": {
"lan": {
"address": "127.0.0.1",
"port": 8000
}
},
"Port": 8000,
"Check": {
"CheckID": "service:redis1",
"Name": "Redis health check",
"Notes": "TCP health check",
"ServiceID": "redis1",
"TCP": "localhost:8888",
"Interval": "5s",
"Timeout": "1s",
"DeregisterCriticalServiceAfter": "600s"
}
}
```

1. Run `curl --request PUT --data @payload.json http://localhost:8500/v1/agent/service/register`
1. Look at the UI, and click on the redis1 service
1. You will notice that the Output field is empty
1. If you leave everything as is, in about 7 min, the Output field will be populated with `dial tcp [::1]:8888: connect: connection refused`
1. If you ` curl localhost:8500/v1/agent/checks` you will see the healthcheck Output field has been set, but it is not showing up in the UI until 7 min later.
1. One other note, if you re run `curl --request PUT --data @payload.json http://localhost:8500/v1/agent/service/register` within the 7 min, the Output field gets populated

### Consul info for both Client and Server

Only ran one consul agent, using `consul agent -dev` locally.

Starting Consul agent
```
Version: '1.9.0-dev'
Node ID: 'a14f00c2-c789-a951-31f7-bf9c3003940f'
Node name: 'dhanushkodi.local'
Datacenter: 'dc1' (Segment: '')
Server: true (Bootstrap: false)
Client Addr: [127.0.0.1] (HTTP: 8500, HTTPS: -1, gRPC: 8502, DNS: 8600)
Cluster Addr: 127.0.0.1 (LAN: 8301, WAN: 8302)
Encrypt: Gossip: false, TLS-Outgoing: false, TLS-Incoming: false, Auto-Encrypt-TLS: false
```

Server info (`consul info`)

```
agent:
check_monitors = 0
check_ttls = 0
checks = 1
services = 1
build:
prerelease = dev
revision = 52f3714c
version = 1.9.0
consul:
acl = disabled
bootstrap = false
known_datacenters = 1
leader = true
leader_addr = 127.0.0.1:8300
server = true
raft:
applied_index = 27
commit_index = 27
fsm_pending = 0
last_contact = 0
last_log_index = 27
last_log_term = 2
last_snapshot_index = 0
last_snapshot_term = 0
latest_configuration = [{Suffrage:Voter ID:a14f00c2-c789-a951-31f7-bf9c3003940f Address:127.0.0.1:8300}]
latest_configuration_index = 0
num_peers = 0
protocol_version = 3
protocol_version_max = 3
protocol_version_min = 0
snapshot_version_max = 1
snapshot_version_min = 0
state = Leader
term = 2
runtime:
arch = amd64
cpu_count = 16
goroutines = 105
max_procs = 16
os = darwin
version = go1.15.3
serf_lan:
coordinate_resets = 0
encrypted = false
event_queue = 1
event_time = 2
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 1
members = 1
query_queue = 0
query_time = 1
serf_wan:
coordinate_resets = 0
encrypted = false
event_queue = 0
event_time = 1
failed = 0
health_score = 0
intent_queue = 0
left = 0
member_time = 1
members = 1
query_queue = 0
query_time = 1
```

### Operating system and Environment details

OS, Architecture, and any other information you can provide about the environment.
Running locally on a macbook pro.
```
os = darwin
version = go1.15.3
```
### Log Fragments

Include appropriate Client or Server log fragments. If the log is longer than a few dozen lines, please include the URL to the [gist](https://gist.github.com/) of the log instead of posting it in the issue. Use `-log-level=TRACE` on the client and server to capture the maximum log detail.

The agent logs show:
`2020-11-05T12:16:42.412-0800 [WARN] agent: Check socket connection failed: check=service:redis1 error="dial tcp [::1]:8888: connect: connection refused"`
far before the UI shows the Output error message.