Fix wrong table name (#30557) (#30652)

Backport #30557 

The table name should be `oauth2_application` but `o_auth2_application`

Caused by

https://github.com/go-gitea/gitea/pull/21316/files#diff-9610efbc608a41f1f2eaff5790423f0a187906f6ff0beb23a5e8d18366cc2ccfR38

models/auth/oauth2_test.go

@@ -13,8 +13,6 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-//////////////////// Application
-
 func TestOAuth2Application_GenerateClientSecret(t *testing.T) {
 	assert.NoError(t, unittest.PrepareTestDatabase())
 	app := unittest.AssertExistsAndLoadBean(t, &auth_model.OAuth2Application{ID: 1})

models/migrations/v1_18/v230.go

@@ -9,9 +9,9 @@ import (
 
 // AddConfidentialColumnToOAuth2ApplicationTable: add ConfidentialClient column, setting existing rows to true
 func AddConfidentialClientColumnToOAuth2ApplicationTable(x *xorm.Engine) error {
-	type OAuth2Application struct {
+	type oauth2Application struct {
+		ID                 int64
 		ConfidentialClient bool `xorm:"NOT NULL DEFAULT TRUE"`
 	}
-
-	return x.Sync(new(OAuth2Application))
+	return x.Sync(new(oauth2Application))
 }

models/migrations/v1_18/v230_test.go

@@ -13,12 +13,12 @@ import (
 
 func Test_AddConfidentialClientColumnToOAuth2ApplicationTable(t *testing.T) {
 	// premigration
-	type OAuth2Application struct {
+	type oauth2Application struct {
 		ID int64
 	}
 
 	// Prepare and load the testing database
-	x, deferable := base.PrepareTestEnv(t, 0, new(OAuth2Application))
+	x, deferable := base.PrepareTestEnv(t, 0, new(oauth2Application))
 	defer deferable()
 	if x == nil || t.Failed() {
 		return
@@ -36,7 +36,7 @@ func Test_AddConfidentialClientColumnToOAuth2ApplicationTable(t *testing.T) {
 	}
 
 	got := []ExpectedOAuth2Application{}
-	if err := x.Table("o_auth2_application").Select("id, confidential_client").Find(&got); !assert.NoError(t, err) {
+	if err := x.Table("oauth2_application").Select("id, confidential_client").Find(&got); !assert.NoError(t, err) {
 		return
 	}