Drop migration for ForeignReference (#23605)

Fix
https://github.com/go-gitea/gitea/issues/21086#issuecomment-1476560381

Related to #21721

models/migrations/v1_17/v211.go

@@ -4,22 +4,9 @@
 package v1_17 //nolint
 
 import (
-	"fmt"
-
 	"xorm.io/xorm"
 )
 
-func CreateForeignReferenceTable(x *xorm.Engine) error {
-	type ForeignReference struct {
-		// RepoID is the first column in all indices. now we only need 2 indices: (repo, local) and (repo, foreign, type)
-		RepoID       int64  `xorm:"UNIQUE(repo_foreign_type) INDEX(repo_local)" `
-		LocalIndex   int64  `xorm:"INDEX(repo_local)"` // the resource key inside Gitea, it can be IssueIndex, or some model ID.
-		ForeignIndex string `xorm:"INDEX UNIQUE(repo_foreign_type)"`
-		Type         string `xorm:"VARCHAR(16) INDEX UNIQUE(repo_foreign_type)"`
-	}
-
-	if err := x.Sync2(new(ForeignReference)); err != nil {
-		return fmt.Errorf("Sync2: %w", err)
-	}
-	return nil
+func CreateForeignReferenceTable(_ *xorm.Engine) error {
+	return nil // This table was dropped in v1_19/v237.go
 }