refactor: use default error response for swagger (#40048)

ref: https://github.com/go-gitea/gitea/pull/39942#discussion_r4393487959

services/context/api.go

@@ -66,54 +66,14 @@ type APIError struct {
 	URL     string `json:"url"`
 }
 
-// APIValidationError is error format response related to input validation
-// swagger:response validationError
-type APIValidationError struct {
-	Message string `json:"message"`
-	URL     string `json:"url"`
-}
-
-// APIInvalidTopicsError is error format response to invalid topics
-// swagger:response invalidTopicsError
-type APIInvalidTopicsError struct {
-	Message       string   `json:"message"`
-	InvalidTopics []string `json:"invalidTopics"`
-}
-
 // APIEmpty is an empty response
 // swagger:response empty
 type APIEmpty struct{}
 
-// APIForbiddenError is a forbidden error response
-// swagger:response forbidden
-type APIForbiddenError struct {
-	APIError
-}
-
-// APIUnauthorizedError is an unauthorized error response
-// swagger:response unauthorized
-type APIUnauthorizedError struct {
-	APIError
-}
-
-// APINotFound is a not found empty response
-// swagger:response notFound
-type APINotFound struct{}
-
-// APIConflict is a conflict empty response
-// swagger:response conflict
-type APIConflict struct{}
-
 // APIString is a string response
 // swagger:response string
 type APIString string
 
-// APIRepoArchivedError is an error that is raised when an archived repo should be modified
-// swagger:response repoArchivedError
-type APIRepoArchivedError struct {
-	APIError
-}
-
 // APIErrorInternal responds with error message, status is 500
 func (ctx *APIContext) APIErrorInternal(err error) {
 	ctx.apiErrorInternal(1, err)