fix: prevent overflow and misaligned read in build-id parsing

[edznux-dd]

What does this PR do?:

This PR fixes an overflow and misaligned read in build-id parsing.
These issues where found by running the fuzz harnesses.

Motivation:

Fix overflow and UB!

Additional Notes:

How to test the change?:

For Datadog employees:

• If this PR touches code that signs or publishes builds or packages, or handles
  credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.
• This PR doesn't touch any of that.
• JIRA: [JIRA-XXXX]

Unsure? Have a question? Request a review!

[datadog-datadog-prod-us1-2]

✨ Fix all issues with BitsAI

⚠️ Warnings

🚦 2 Pipeline jobs failed

CI Run | summarize-tests     

🛟 This job is unlikely to succeed on retry. Please review your pipeline configuration.

Missing required environment variables. Ensure 'id-token: write' is set in your workflow permissions.

Code Quality Checks | scan-build     

🛟 This job is unlikely to succeed on retry. Please review your pipeline configuration.

Missing required environment variables; have you set 'id-token: write' in your workflow permissions?

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