Fix timezone_id not being set

[emawby]

Description

One Line Summary

This fixes an issue where timezone_id was not being set as a property on users.

Details

This issue resulted in scheduled notifications being received at the wrong time.
In order to send the timezone_id we are adding a properties map in the createUser call. The properties set there (only timezone_id) will be hydrated to the properties model when the response is received.
fixes #1829

Motivation

Fix scheduled notifications

Scope

user properties during createUser

Testing

Unit testing

Added properties object to existing unit tests

Manual testing

Tested scheduled notifications on a physical device.

Affected code checklist

• Notifications
  • Display
  • Open
  • Push Processing
  • Confirm Deliveries
• Outcomes
• Sessions
• In-App Messaging
• REST API requests
• Public API changes

Checklist

Overview

• I have filled out all REQUIRED sections above
• PR does one thing
  • If it is hard to explain how any codes changes are related to each other then it most likely needs to be more than one PR
• Any Public API changes are explained in the PR details and conform to existing APIs

Testing

• I have included test coverage for these changes, or explained why they are not needed
• All automated tests pass, or I explained why that is not possible
• I have personally tested this on my device, or explained why that is not possible

Final pass

• Code is as readable as possible.
  • Simplify with less code, followed by splitting up code into well named functions and variables, followed by adding comments to the code.
• I have reviewed this PR myself, ensuring it meets each checklist item
  • WIP (Work In Progress) is ok, but explain what is still in progress and what you would like feedback on. Start the PR title with "WIP" to indicate this.

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This change is 

[nan-li]

LGTM, noting we don't save the timezone_id to the properties model locally until the next session via hydration from a fetch user.

[nan-li]

I would prefer to remove !! and change TimeUtils.getTimeZoneId() to return a non-optional String. That method seems like it should always return a String.

[emawby]

Fixed! Ya that method always returns a string so I changed its return type to be non-optional