[@loopback/sequelize] SQL select error if an empty string "order" is passed to SequelizeRepository find / findOne methods

[KalleV]

Describe the bug

Passing an empty "order" property through an API or direct repository call leads to a broken select statement.

Example filter that will lead to the error:

{
    "order": ""
}

Logs

at Query.run (node_modules/sequelize/src/dialects/mysql/query.js:46:25)
at node_modules/sequelize/src/sequelize.js:650:28
  code: 'ER_BAD_FIELD_ERROR',
  errno: 1054,
  sqlState: '42S22',
  sqlMessage: "Unknown column 'MyTable.' in 'order clause'",
  sql: "SELECT ... ORDER BY `MyTable`.`` ASC;"
}

Additional information

No response

Reproduction

#10279