Reimplement GetUserOrgsList to make it simple and clear (#32486)

Reimplement GetUserOrgsList and also move some functions and test to
org_list file.

---------

Co-authored-by: Zettat123 <zettat123@gmail.com>

models/organization/org_list_test.go

@@ -0,0 +1,62 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package organization_test
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/models/db"
+	"code.gitea.io/gitea/models/organization"
+	"code.gitea.io/gitea/models/unittest"
+	user_model "code.gitea.io/gitea/models/user"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCountOrganizations(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	expected, err := db.GetEngine(db.DefaultContext).Where("type=?", user_model.UserTypeOrganization).Count(&organization.Organization{})
+	assert.NoError(t, err)
+	cnt, err := db.Count[organization.Organization](db.DefaultContext, organization.FindOrgOptions{IncludePrivate: true})
+	assert.NoError(t, err)
+	assert.Equal(t, expected, cnt)
+}
+
+func TestFindOrgs(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+
+	orgs, err := db.Find[organization.Organization](db.DefaultContext, organization.FindOrgOptions{
+		UserID:         4,
+		IncludePrivate: true,
+	})
+	assert.NoError(t, err)
+	if assert.Len(t, orgs, 1) {
+		assert.EqualValues(t, 3, orgs[0].ID)
+	}
+
+	orgs, err = db.Find[organization.Organization](db.DefaultContext, organization.FindOrgOptions{
+		UserID:         4,
+		IncludePrivate: false,
+	})
+	assert.NoError(t, err)
+	assert.Len(t, orgs, 0)
+
+	total, err := db.Count[organization.Organization](db.DefaultContext, organization.FindOrgOptions{
+		UserID:         4,
+		IncludePrivate: true,
+	})
+	assert.NoError(t, err)
+	assert.EqualValues(t, 1, total)
+}
+
+func TestGetUserOrgsList(t *testing.T) {
+	assert.NoError(t, unittest.PrepareTestDatabase())
+	orgs, err := organization.GetUserOrgsList(db.DefaultContext, &user_model.User{ID: 4})
+	assert.NoError(t, err)
+	if assert.Len(t, orgs, 1) {
+		assert.EqualValues(t, 3, orgs[0].ID)
+		// repo_id: 3 is in the team, 32 is public, 5 is private with no team
+		assert.EqualValues(t, 2, orgs[0].NumRepos)
+	}
+}