[SEC] Notify owner about TOTP enrollment

- In the spirit of #4635
- Notify the owner when their account is getting enrolled into TOTP. The
message is changed according if they have security keys or not.
- Integration test added.

models/unittest/unit_tests.go

@@ -9,6 +9,7 @@ import (
 	"code.gitea.io/gitea/models/db"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 	"xorm.io/builder"
 )
 
@@ -130,6 +131,12 @@ func AssertSuccessfulInsert(t assert.TestingT, beans ...any) {
 	assert.NoError(t, err)
 }
 
+// AssertSuccessfulDelete assert that beans is successfully deleted
+func AssertSuccessfulDelete(t require.TestingT, beans ...any) {
+	err := db.DeleteBeans(db.DefaultContext, beans...)
+	require.NoError(t, err)
+}
+
 // AssertCount assert the count of a bean
 func AssertCount(t assert.TestingT, bean, expected any) bool {
 	return assert.EqualValues(t, expected, GetCount(t, bean))