fix(api): adding issue labels by name attaches both the repo and the org label (#39873)

Fixes #39651

When an org-owned repo has a repo label and an org label with the same
name, `POST`/`PUT /repos/{owner}/{repo}/issues/{index}/labels` with
label names attached both of them.

---------

Signed-off-by: Nazem <214302554+nazem-droubi@users.noreply.github.com>
Co-authored-by: Nazem <214302554+nazem-droubi@users.noreply.github.com>
Co-authored-by: silverwind <me@silverwind.io>

templates/swagger/v1-openapi3.generated.json

@@ -7487,7 +7487,7 @@
         "description": "IssueLabelsOption a collection of labels",
         "properties": {
           "labels": {
-            "description": "Labels can be a list of integers representing label IDs\nor a list of strings representing label names",
+            "description": "Labels can be a list of integers representing label IDs\nor a list of strings representing label names.\nIf a repository label and an organization label share a name,\nthe repository label is used.",
             "items": {},
             "type": "array",
             "x-go-name": "Labels"

templates/swagger/v1-swagger.generated.json

@@ -30599,7 +30599,7 @@
       "type": "object",
       "properties": {
         "labels": {
-          "description": "Labels can be a list of integers representing label IDs\nor a list of strings representing label names",
+          "description": "Labels can be a list of integers representing label IDs\nor a list of strings representing label names.\nIf a repository label and an organization label share a name,\nthe repository label is used.",
           "type": "array",
           "items": {},
           "x-go-name": "Labels"