fix: Error propagation for kinesis send errors

[huntharo]

• Errors thrown by KinesisClient.send were being hidden in an error collection that could not be accessed by the caller
• Add unit tests for this type of error
• Fix the error propagation
• Note: this is NOT the same as a throttled write within a batch, which does not throw an error but marks specified records in the result as having failed

[github-actions]

📊 Node.js Code Coverage Report

File	Lines	Lines Hit / Found	Uncovered Lines	Branches
src/kinesis-background-writer.ts	✅ 100.0%	137 / 137	0	100.0%
src/kinesis-retrier.ts	✅ 94.6%	210 / 222	12	77.8%
Overall	✅ 96.7%	347 / 359	12	82.8%