Add missing cloexec flags in logging system

Context

This MR fixes an issue where forked processes (i.e. validator process and upcoming rpc process) would inherit a dailylog fd which would be kept alive and ending up locking disk space. This is fixed by adding a CLOEXEC flag.

Manually testing the MR

CI

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, CHANGES.rst at the root of the repository for everything else).
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