Fix extractTableName to check identifier before appending dot

Addresses PR feedback: Only append dot after database identifier
if table identifier is not null to avoid trailing dots.

Author: devdavidkarlsson

jdbc-v2/src/main/java/com/clickhouse/jdbc/internal/SqlParserFacade.java

@@ -283,7 +283,11 @@ private String extractTableName(ClickHouseParser.TableIdentifierContext tableId)
                         }
                         tableName.append(SQLUtils.unquoteIdentifier(dbParts.get(i).getText()));
                     }
-                    tableName.append('.');
+                    
+                    // Only append dot if table identifier exists
+                    if (tableId.identifier() != null) {
+                        tableName.append('.');
+                    }
                 }
 
                 // Handle table identifier