NIFI-9504 Upgrade Logback from 1.2.8 to 1.2.9

[exceptionfactory]

Description of PR

NIFI-9504 Upgrades Logback from 1.2.8 to 1.2.9 in order to address potential vulnerabilities associated with non-standard logging configurations as described in CVE-2021-42550.

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[exceptionfactory]

Push additional commit upgrading Log4j 2 from 2.16.0 to 2.17.0 for NIFI-9505.

[ChrisSamo632]

Thanks for your contribution @exceptionfactory, 👍 will merge