Enable tenv and testifylint rules (#32852)

Enables tenv and testifylint linters
closes: https://github.com/go-gitea/gitea/issues/32842

models/organization/org_list_test.go

@@ -40,7 +40,7 @@ func TestFindOrgs(t *testing.T) {
 		IncludePrivate: false,
 	})
 	assert.NoError(t, err)
-	assert.Len(t, orgs, 0)
+	assert.Empty(t, orgs)
 
 	total, err := db.Count[organization.Organization](db.DefaultContext, organization.FindOrgOptions{
 		UserID:         4,

models/organization/org_test.go

@@ -283,7 +283,7 @@ func TestGetOrgUsersByOrgID(t *testing.T) {
 		OrgID:       unittest.NonexistentID,
 	})
 	assert.NoError(t, err)
-	assert.Len(t, orgUsers, 0)
+	assert.Empty(t, orgUsers)
 }
 
 func TestChangeOrgUserStatus(t *testing.T) {