fix: log batch trigger

[0618]

Description of changes

After #13738, there are 2 problems found:

1. the log only works if accountForFailures is true
2. if CODEBUILD_WEBHOOK_TRIGGER is unset or null, accountForFailures would become the 5th param

In this PR:

• moved the CODEBUILD_WEBHOOK_TRIGGER log out of the accountForFailures check
• set a default value empty for CODEBUILD_WEBHOOK_TRIGGER

Issue #, if available

Description of how you validated changes

tested in codebuild

Checklist

• PR description included
• yarn test passes
• Tests are changed or added
• Relevant documentation is changed or added (and PR referenced)
• New AWS SDK calls or CloudFormation actions have been added to relevant test and service IAM policies
• Pull request labels are added

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