fix: add null checks for appRecord and appRecord.instanceMap, fix #1892

[claylevering]

fix(index.ts): add null checks for appRecord and appRecord.instanceMap to prevent errors when accessing properties

Description

Fixes #1892

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Pull Request Guidelines and follow the Commit Convention.
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• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).