MatDialog `open` method `R` generic is too loose

Because the `R` generic on `MatDialog.open` isn't constrained by arguments to the function, it's effectively always `any`. We should remove the method generic and change the return generic to `{}`, which will force people to explicitly state which type it is when consuming it.

首先定位 MatDialog.open 方法的声明，并检查其泛型 R 是如何定义和返回的。按照描述更新泛型类型，然后验证对话框结果的使用者必须明确提供其预期类型，并且现有的 TypeScript 检查仍然通过。

由索引模型根据 Issue 内容生成。