Fix LiveTradingRealTimeHandler pack-up creating the potential for a N…

[ghost]

…ullReferenceException

Description

Changes the order of pack-up in LiveTradingRealTimeHandler.Exit() to avoid a potential NullReferenceException.

Related Issue

Closes #4532

Motivation and Context

The exception was thrown in one of our environments and meant QC didn't pack-up cleanly. Functionality wasn't impacted, as QC was packing down anyway. However it still shouldn't be thrown.

Requires Documentation Change

N/A

How Has This Been Tested?

Test code was provided in the issue, showing how to reproduce the exception.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• Refactor (non-breaking change which improves implementation)
• Performance (non-breaking change which improves performance. Please add associated performance test and results)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Non-functional change (xml comments/documentation/etc)

Checklist:

• My code follows the code style of this project.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes. Reason: Unable to cover in a unit test.
• All new and existing tests passed.
• My branch follows the naming convention bug-<issue#>-<description> or feature-<issue#>-<description>

[Martin-Molinero]

Nice fix, thank you 👍