Add missing nullcheck for RegistryInitService

[Freezor]

Description

Please include a summary of the changes and the related issue. Please also include relevant motivation and context. List
any dependencies that are required for this change.

Motivation and Context

Fixes # (issue)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Screenshots (if appropriate):

Checklist:

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works