feat(typescript): export the LDProps interface for access in application code (#321)

**Requirements**

- [ ] I have added test coverage for new or changed functionality
- [x] I have followed the repository's [pull request submission
guidelines](../blob/main/CONTRIBUTING.md#submitting-pull-requests)
- [ ] I have validated my changes against all supported platform
versions

**Related issues**

#322

**Describe the solution you've provided**

With this change, it is possible to import the LDProps type from the
library like this:
```ts
import type {LDProps} from 'launchdarkly-react-client-sdk'
```

**Describe alternatives you've considered**

The current workarounds have involved duplicating the TS interface into
the codebase or attempting to infer it from the `withLDConsumer`
parameter types. The latter option does not work well with IDEs and
IntelliSense.

**Additional context**

N/A

---------

Co-authored-by: Ryan Lamb <[email protected]>

Author: kallevmercury

src/types.ts

@@ -165,6 +165,8 @@ export interface AllFlagsLDClient {
  */
 export type LDFlagKeyMap = Record<string, string>;
 
+export { type LDProps } from './withLDConsumer';
+
 /**
  * The sdk context stored in the Provider state and passed to consumers.
  */