table expandedRowKeys support two-way binding

[Hccake]

• I have searched the issues of this repository and believe that this is not a duplicate.

What problem does this feature solve?

In version 1.x, you can use the :expanded-row-keys.sync="expandedRowKeys" method to obtain the ability of two-way binding.

But in the 3.x version, you must manually bind the expandedRowsChange event.

If you can keep the same as in 1.x and emit the update:expandedRowKeys event, you can simply use it v-model:expandedRowKeys="expandedRowKeys" to get the expandedRowKeys of the two-way binding

What does the proposed API look like?

expandedRowKeys supports two-way binding.

[Hccake]

issues 助手有问题，生产的连接中如果携带了 lables 参数时，就会导致 github 异常

@tangjinzhou

[github-actions]

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