Weldr: explicitly specify boot mode in AWS upload target

Explicitly specify the AMI boot mode in AWS upload target in Weldr API
compose handler. The value is determined based on image type's boot
mode.

Signed-off-by: Tomáš Hozza <thozza@redhat.com>

internal/weldr/api_test.go

@@ -16,6 +16,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/aws/aws-sdk-go/service/ec2"
 	"github.com/osbuild/osbuild-composer/internal/blueprint"
 	"github.com/osbuild/osbuild-composer/internal/common"
 	"github.com/osbuild/osbuild-composer/internal/distro"
@@ -998,6 +999,7 @@ func TestCompose(t *testing.T) {
 						SecretAccessKey: "secretkey",
 						Bucket:          "clay",
 						Key:             "imagekey",
+						BootMode:        common.ToPtr(ec2.BootModeValuesUefiPreferred),
 					},
 				},
 			},