fix(api): edit and delete repository labels by name (#39974)

Repo and org label endpoints accepted a label name for GET but only a
numeric ID for PATCH and DELETE, which breaks label-sync style tools.

- PATCH and DELETE on `/repos/{owner}/{repo}/labels/{id}` and
`/orgs/{org}/labels/{id}` accept a label name when the value is not
numeric, numeric values stay IDs
- A name shared by several labels returns 400 instead of acting on an
arbitrary one
- Deleting a missing label returns 404 instead of 204
- The swagger `id` parameter of these endpoints is now a string

Fixes: https://github.com/go-gitea/gitea/issues/34937
Co-authored-by: Hello-Liar <80651389+Hello-Liar@users.noreply.github.com>
Co-authored-by: silverwind <me@silverwind.io>

tests/integration/api_issue_label_test.go

@@ -6,6 +6,7 @@ package integration
 import (
 	"fmt"
 	"net/http"
+	"net/url"
 	"strings"
 	"testing"
 
@@ -116,7 +117,7 @@ func TestAPIModifyLabels(t *testing.T) {
 			assert.Equal(t, strings.TrimLeft(dbLabel.Color, "#"), apiLabel.Color)
 
 			// EditLabel
-			newName := "LabelNewName"
+			newName := "scope/new name"
 			newColor := "09876a"
 			newColorWrong := "09g76a"
 			req = NewRequestWithJSON(t, "PATCH", singleURLStr, &api.EditLabelOption{
@@ -130,11 +131,16 @@ func TestAPIModifyLabels(t *testing.T) {
 				Color: &newColorWrong,
 			}).AddTokenAuth(token)
 			MakeRequest(t, req, http.StatusUnprocessableEntity)
+			nameURLStr := urlStr + "/" + url.PathEscape(newName)
+			req = NewRequestWithJSON(t, "PATCH", nameURLStr, &api.EditLabelOption{}).AddTokenAuth(token)
+			resp = MakeRequest(t, req, http.StatusOK)
+			assert.Equal(t, dbLabel.ID, DecodeJSON(t, resp, &api.Label{}).ID)
 
 			// DeleteLabel
-			req = NewRequest(t, "DELETE", singleURLStr).
-				AddTokenAuth(token)
+			req = NewRequest(t, "DELETE", nameURLStr).AddTokenAuth(token)
 			MakeRequest(t, req, http.StatusNoContent)
+			req = NewRequest(t, "DELETE", singleURLStr).AddTokenAuth(token)
+			MakeRequest(t, req, http.StatusNotFound)
 		})
 	}
 }