feat: implement switchover for blobby v1

[pl]

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Problem

We're ready to fully transition to Blobby V2, but we're missing the switchover logic in V1.

Changes

• Adds support for the SESSION_RECORDING_V2_METADATA_SWITCHOVER env variable
• Implements switchover logic for session replay events
• Implements switchover logic for console logs

Did you write or update any docs for this change?

• [ ] I've added or updated the docs
• [ ] I've reached out for help from the docs team
• [X] No docs needed for this change

How did you test this code?

Added unit tests.