feat(CdkMenu): Option to disable typeahead in CdkMenu

### Feature Description

We would like to add an option in the `CdkMenu` to disable the integrated TypeAhead feature.

Currently, the menu activates the TypeAhead for its `FocusKeyManager` automatically:
https://github.com/angular/components/blob/e91d5091bbf3d44cc168be458269d260a0c22c27/src/cdk/menu/menu-base.ts#L175

The proposal would be to add an input like `cdkMenuTypeAhead: boolean` which defaults to true but can be used to skip the TypeAhead activation:
```ts
this.keyManager = new FocusKeyManager(this.items).withWrap().withHomeAndEnd();
if (this.cdkMenuTypeAhead) {
this.keyManager = this.keyManager.withTypeAhead()
}
```

#### Alternative

An alternative approach might be a combination of the following features, so the described use case can be accomplished by the `CdkMenu` itself.
1. Make the current search term (`_pressedLetters`) publicly available, so it can be displayed.
2. Two variants to extend the current search logic:
2.a Add a secondary `includes` search to the current `startsWith`.
2.b Make the search logic customizable with configurable predicate function.

### Use Case

The use case is a custom search feature for our menus, which conflicts with the integrated TypeAhead.
We want to display the current search term and search by `startsWith` & `includes`.

 

***

**🗨 I would appreciate some feedback, if this feature has a chance of being accepted. Then I can prepare a PR for this.**

从 src/cdk/menu/menu-base.ts 中链接行附近的 FocusKeyManager 设置开始，然后跟踪 CdkMenu 输入的声明方式以及 typeahead 的激活方式。当菜单可以选择退出 typeahead，同时保留当前默认行为时，此更改即完成；如果有现成的菜单测试，请查看它们以验证两条路径。

由索引模型根据 Issue 内容生成。