fix config.set('customizeIgnoreSelectors') not work

[mywei1989]

根据此issue 2223 发现该方法会报错导致无法正常工作，经过调试提出修改方案如commit所示。
经测试后该方法可以正常使用。

`
// 任意可获取到config的地方

config.set('customizeIgnoreSelectors', ['.next-btn'])
`

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[liujuping]

这里的 customizeIgnoreSelectors 是 function。配置方式示例：

config.set('customizeIgnoreSelectors', () => ['.next-btn'])

[mywei1989]

这里的 customizeIgnoreSelectors 是 function。配置方式示例：

config.set('customizeIgnoreSelectors', () => ['.next-btn'])

ok 那是我理解错了····