Provide the ability to remove code needed only in dev mode from the production bundle

### Which @angular/* package(s) are relevant/related to the feature request?

core

### Description

Several NgRx libraries have features/checks that are only used in development mode (e.g. store runtime checks, component store lifecycle hooks check, store devtools, etc).

### Proposed solution

Expose the `ngDevMode`/`isNgDevMode` variable to the public API, so it can be used in Angular libraries that have dev mode-related functionalities, but also in user codebases if needed.

This feature could significantly reduce the size of production bundles in many Angular codebases.

### Alternatives considered

Currently, we can use `ngDevMode` to remove dev mode-related logic from the production bundle in the following way:

```ts
declare const ngDevMode: boolean;
const isNgDevMode = typeof ngDevMode === 'undefined' || !!ngDevMode;

// ...

if (isNgDevMode) {
console.warn('@ngrx/store: ...');
}
```

However, this global variable is not part of the public API and it can be risky to rely on it.

Start in Angular's core package by tracing the existing ngDevMode/isNgDevMode implementation and how public API exports are defined. Review the development-only checks described in the issue and the production-bundle behavior. Done means the variable is publicly available to Angular libraries and user code, with relevant tests confirming the intended production build behavior.

Written by the indexing model from the issue text.