Chore: Make cgo optional (for sqlite) (#108756)

* make cgo optional for sqlite

* update go.mod; check error code differently

* reduce api surface even more

* move test errors into sqlite package

* add a comment

pkg/services/sqlstore/migrator/sqlite_dialect.go

@@ -1,12 +1,10 @@
 package migrator
 
 import (
-	"errors"
 	"fmt"
 	"strings"
 
-	"github.com/mattn/go-sqlite3"
-
+	"github.com/grafana/grafana/pkg/util/sqlite"
 	"github.com/grafana/grafana/pkg/util/xorm"
 )
 
@@ -139,27 +137,12 @@ func (db *SQLite3) TruncateDBTables(engine *xorm.Engine) error {
 	return nil
 }
 
-func (db *SQLite3) isThisError(err error, errcode int) bool {
-	var driverErr sqlite3.Error
-	if errors.As(err, &driverErr) {
-		if int(driverErr.ExtendedCode) == errcode {
-			return true
-		}
-	}
-
-	return false
-}
-
 func (db *SQLite3) ErrorMessage(err error) string {
-	var driverErr sqlite3.Error
-	if errors.As(err, &driverErr) {
-		return driverErr.Error()
-	}
-	return ""
+	return sqlite.ErrorMessage(err)
 }
 
 func (db *SQLite3) IsUniqueConstraintViolation(err error) bool {
-	return db.isThisError(err, int(sqlite3.ErrConstraintUnique)) || db.isThisError(err, int(sqlite3.ErrConstraintPrimaryKey))
+	return sqlite.IsUniqueConstraintViolation(err)
 }
 
 func (db *SQLite3) IsDeadlock(err error) bool {