What does this implement/fix?

Also check name of process identified by PID file when trying to identify if FTL is already running to resolve a rare edge-case with reboot-persistent PID files and PID collisions. So far, this error has only been observed in certain docker configurations that lack the mandated PID file deletion after process shutdown

With this new check, nothing changes in the "normal" case:

2025-08-03 21:18:38.846 CEST [2803950M] CRIT: pihole-FTL is already running (PID 1400358)!

However, if the PID actually belong to a different process (see described rare edge-case above), FTL does now not (incorrectly) stop any longer but merely logs

2025-08-03 21:18:05.180 CEST [2803601M] WARNING: Found process "grep" at PID 1400357 suggested by PID file, ignoring

This PR has been sparked by pi-hole/docker-pi-hole#1789 (comment)

Related issue or feature (if applicable): N/A

Pull request in docs with documentation (if applicable): N/A

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