enforce validation for missing service name in registration

[markcampv]

Description

Adds validation to the catalog register endpoint to ensure that a service name (Service.Service) is provided when registering a service. This prevents registrations with empty service names, which resulted in the Services page in the Consul UI being broken.

If both Service.ID and Service.Service are empty, the API now returns an error message.

Testing & Reproduction steps

• Added unit test TestCatalog_Register_RejectsMissingServiceName in catalog_endpoint_test.go
• Manually validated behavior using:

curl -X PUT http://localhost:8500/v1/catalog/register \
  -H "Content-Type: application/json" \
  --data-raw '{
    "Datacenter": "dc1",
    "Node": "my_node",
    "Address": "123.456.78.9",
    "Service": {
      "ID": "",
      "Service": "",
      "Port": 9001
    }
  }'

service name (Service.Service) is required; both Service ID (Service.ID) and Service Name cannot be empty

Links

PR Checklist

• [x ] updated test coverage
• external facing docs updated
• appropriate backport labels added
• [x ] not a security concern

[sreeram77]

Hey @markcampv, thank you for the contribution. Can you please add a changelog for this PR? ref

[markcampv]

Hey @markcampv, thank you for the contribution. Can you please add a changelog for this PR? ref

Done! I've also added a backport label since this fix is currently needed for a customer on 1.20.5+ent

[sreeram77]

LGTM!

[hc-github-team-consul-core]

📣 Hi @markcampv! a backport is missing for this PR [22381] for versions [1.18,1.19,1.20,1.21] please perform the backport manually and add the following snippet to your backport PR description:

<details>
	<summary> Overview of commits </summary>
		- <<backport commit 1>>
		- <<backport commit 2>>
		...
</details>

[hc-github-team-consul-core]

📣 Hi @markcampv! a backport is missing for this PR [22381] for versions [1.18,1.19,1.20,1.21] please perform the backport manually and add the following snippet to your backport PR description:

<details>
	<summary> Overview of commits </summary>
		- <<backport commit 1>>
		- <<backport commit 2>>
		...
</details>

[hc-github-team-consul-core]

📣 Hi @markcampv! a backport is missing for this PR [22381] for versions [1.18,1.19,1.20,1.21] please perform the backport manually and add the following snippet to your backport PR description:

<details>
	<summary> Overview of commits </summary>
		- <<backport commit 1>>
		- <<backport commit 2>>
		...
</details>

[hc-github-team-consul-core]

📣 Hi @markcampv! a backport is missing for this PR [22381] for versions [1.18,1.19,1.20,1.21] please perform the backport manually and add the following snippet to your backport PR description:

<details>
	<summary> Overview of commits </summary>
		- <<backport commit 1>>
		- <<backport commit 2>>
		...
</details>

[hc-github-team-consul-core]

📣 Hi @markcampv! a backport is missing for this PR [22381] for versions [1.18,1.19,1.20,1.21] please perform the backport manually and add the following snippet to your backport PR description:

<details>
	<summary> Overview of commits </summary>
		- <<backport commit 1>>
		- <<backport commit 2>>
		...
</details>