Async load block deprecations?

#### Is your feature request related to a problem? Please describe.
* Adding block deprecations increases the bundle size.

#### Describe the solution you'd like
* Is it possible to async-load the deprecations, or load only if block gets deprecated?

@sgomes mentioned:

>Perhaps making deprecated an async function to an array, rather than a simple array?

```
{
deprecated: async () => {
const deprecatedV1 = await import( './depecrated/v1' );
const deprecatedV2 = await import( './depecrated/v2' );
return [ deprecatedV1.default, deprecatedV2.default ];
},
}
```

>Other code that makes use of these properties would then have to be updated accordingly, and made to be async-safe.

#### Describe alternatives you've considered

* None.

#### Additional context

Splitting this off from a review discussion in https://github.com/Automattic/jetpack/pull/17393/files. @sgomes @simison

Start with the review discussion in PR #17393 and inspect the deprecated/v1 and deprecated/v2 modules referenced in the example. Trace the consumers of the deprecated properties and determine the async-safety and bundle-size requirements; done means an agreed design with the affected consumers updated and the impact verified.

Written by the indexing model from the issue text.