[TASK] Superfluous comparison in CronCommand

Fix superfluous comparison against boolean in
CronCommand::dayMatchesCronCommand

Change-Id: Ia1d852ffbbc772dd89587d304b1234e11e372d2d
Resolves: #54050
Releases: 6.2
Reviewed-on: https://review.typo3.org/25737
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers
Reviewed-by: Markus Klein
Tested-by: Markus Klein