fix: drop only invalid cookieless events

[pl]

Problem

When timestamp validation in cookieless manager fails, it throws an error which is handled by the generic try-catch, causing all cookieless events in the batch to be dropped.

Changes

• Refactors the cookieless manager to drop only the messages with timestamps out of range.
• Adds ingestion warnings for events submitted with out of range timestamps

How did you test this code?

• Added new tests for timestamp validation
• Existing regression tests

[greptile-apps]

_{2 files reviewed, no comments}

_{Edit Code Review Agent Settings | Greptile}