Bail early when provided model name for 'run' is invalid

cmd/run/run.go

@@ -16,6 +16,7 @@ import (
 	"github.com/cli/go-gh/v2/pkg/term"
 	"github.com/github/gh-models/internal/azure_models"
 	"github.com/github/gh-models/internal/ux"
+	"github.com/github/gh-models/pkg/util"
 	"github.com/spf13/cobra"
 	"github.com/spf13/pflag"
 )
@@ -226,15 +227,11 @@ func NewRunCommand() *cobra.Command {
 				modelName = args[0]
 			}
 
-			for _, model := range models {
-				if strings.EqualFold(model.FriendlyName, modelName) || strings.EqualFold(model.Name, modelName) {
-					modelName = model.Name
-					break
-				}
-			}
-
-			if modelName == "" {
-				return errors.New("the specified model name is not supported")
+			validModelName := util.GetValidModelName(modelName, models)
+			if validModelName == nil {
+				return fmt.Errorf("the specified model name is not supported: %s", modelName)
+			} else {
+				modelName = *validModelName
 			}
 
 			initialPrompt := ""