PUT /agent/force-leave endpoint returns status code 500 instead of 404 on missing node

[AHGIJMKLKKZNPJKQR]

Overview of the Issue

The PUT /agent/force-leave/:node_name HTTP endpoint responds with a 500 Internal Server Error instead of 404 Not Found when there is no node with the specified name.

---

Reproduction Steps

1. Start a consul server with version 1.19.1
2. Run curl --verbose --request PUT <server-url>/v1/agent/force-leave/nonexistent-node
3. See that response code is 500

Consul info for both Client and Server

Client info

N/A

Server info

# consul info
agent:
	check_monitors = 0
	check_ttls = 0
	checks = 0
	services = 0
build:
	prerelease =
	revision = bf0166d8
	version = 1.19.0
	version_metadata =
consul:
	acl = disabled
	bootstrap = true
	known_datacenters = 1
	leader = true
	leader_addr = 172.17.0.2:8300
	server = true
raft:
	applied_index = 14
	commit_index = 14
	fsm_pending = 0
	last_contact = 0
	last_log_index = 14
	last_log_term = 2
	last_snapshot_index = 0
	last_snapshot_term = 0
	latest_configuration = [{Suffrage:Voter ID:a245377a-5061-3dc6-e7bf-10cf775b2027 Address:172.17.0.2:8300}]
	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 = 12
	goroutines = 185
	max_procs = 12
	os = linux
	version = go1.22.4
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

HCL:

data_dir = "/consul/data"
server = true
bootstrap = true

Operating system and Environment details

OS: Arch linux (kernel version 6.10.12-hardened1-1-hardened)
This happens for Consul 1.19.1 when run both in docker and on bare-metal

Log Fragments

2024-10-28T12:36:59.145Z [INFO]  agent: Force leaving node: node=this-node-does-not-exist
2024-10-28T12:36:59.145Z [WARN]  agent: Failed to remove node: node=this-node-does-not-exist error="agent: No node found with name 'this-node-does-not-exist'"
2024-10-28T12:36:59.145Z [ERROR] agent.http: Request error: method=PUT url=/v1/agent/force-leave/this-node-does-not-exist from=172.17.0.1:36870 error="agent: No node found with name 'this-node-does-not-exist'"
2024-10-28T12:36:59.145Z [DEBUG] agent.http: Request finished: method=PUT url=/v1/agent/force-leave/this-node-does-not-exist from=172.17.0.1:36870 latency="94.995µs"