Add getNativeSdkVersion to get native sdk version

[tim-lin-bbpos]

Summary

Add getNativeSdkVersion to get native sdk version

Motivation

Add getNativeSdkVersion function to reveal the embedded Android/iOS sdk version.
Reference: https://bugs.bbpos.com/browse/SDK-227

Testing

• I tested this manually
• I added automated tests

Documentation

Select one:

• I have added relevant documentation for my changes.
• This PR does not result in any developer-facing changes.

[nazli-stripe]

try / catch block?

[tim-lin-bbpos]

Receive the const will not cause exception but we can align the usage and prevent future break, will add in following commit.

[tim-lin-bbpos]

I found few different approaches, would like to hear from your opinion:

• Wrap the result with error like confirmRefund() does below to consistently return same type to caller:

export type ConfirmRefundResultType = {
  refund?: Refund.Props;
  error?: StripeError;
};

• Return string when success, return error object when fail like getOfflineStatus() does

export type OfflineStatus = {
  sdk: OfflineStatusDetails;
  reader?: OfflineStatusDetails;
};

• Return empty string or NA when error happen to keep using string type

[nazli-stripe]

i'm peaceful with returning an empty string. i don't expect errors to happen here but juuuuuust in case we don't break

[nazli-stripe]

should we include the isInitialized check here or is that redundant due to how the constants are retrieved from the SDK?

[tim-lin-bbpos]

Because it's just a const inside each sdk, we don't even need to call the terminal instance. So no matter whatever state it should return the same value.

[nazli-stripe]

@bric-stripe @ugochukwu-stripe could you take a look at the native changes?

[bric-stripe]

iOS bits lgtm