PrebidMobile.setExternalUserIds is not adding external users

[kwchan22]

Describe the bug PrebidMobile.setExternalUserIds(...) does not set the userIds in the Prebid bid request user section. However if using TargetingParams.storeExternalUserId then I see the userId in the bid request.

To Reproduce Steps to reproduce the behavior:

1. Git clone Prebid Android SDK Project
2. Go to PrebidDemoKotlin -> CustomApplication.kt
3. Add in onCreate() this code: PrebidMobile.setExternalUserIds(mutableListOf(ExternalUserId("PrebidMobile", "prebidMobile-123", null, null)))
4. Run app with App inspection
5. See under the network inspector -> "/auctions" endpoint, I do not see the user added.

Expected behavior All the users set with PrebidMobile.setExternalUserIds should be added to the Prebid bid request user section.

Screenshots With PrebidMobile.setExternalUserIds, bid request user is empty

With TargetingParams.storeExternalUserId, user has the externalUserId

Desktop (please complete the following information): MacBook Pro Apple M3 Pro

Smartphone (please complete the following information):

• Device: Google Pixel 4
• OS: Android 11

Additional context None