[LOGSC-1794] Change Logs assets file ownership to only Logs-backend

[thibaultkrebs]

Context

Following incident 27749 where an integration was removed without any approval from logs-backend we are now moving back ownership to log files only to the logs-backend team.

Note: I have put it last in the codeowner file to make sure no override will be down for any integration

Jira ticket: https://datadoghq.atlassian.net/browse/LOGSC-1794

Example for ownership: