Modify end time of lambda load span to be last cold start node's end_time

[joeyzhao2018]

What does this PR do?

1. Modify end time of lambda load span to be last cold start node's end_time corresponding nodejs layer PR
2. Also ignore AttributeError when checking whether is_authorizer_response

Motivation

Testing Guidelines

Additional Notes

Types of Changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

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