authorizer: add parens

[travisdowns]

To silence -Wlogical-op-parentheses warning (which oddly only occurs on remote icecc machines though it looks to me like it should always fire).

Backports Required

• none - not a bug fix
• none - this is a backport
• none - issue does not exist in previous branches
• none - papercut/not impactful enough to backport
• v23.3.x
• v23.2.x

Release Notes

• none

[oleiman]

Weird. Thanks @travisdowns!

[travisdowns]

It is weird. It looks to me like the warning (actually error due to our use of -Werror) should always fire, but it doesn't. However, ccache and preprocessing can complicate this since the compiler tries to avoid emitting these warnings for certain header files or perhaps all header files in some cases, and ccache likes to pre-process the file in order to check for cache hits and then pass that pre-processed file directly through to the compiler to avoid having the compiler pre-process it again and in some cases this can change the warning/error suppression behavior. Admittedly hand wavy but I thought I'd just fix it versus digging deeper than that.

[vbotbuildovich]

new failures in https://buildkite.com/redpanda/redpanda/builds/46878#018e803e-4297-407a-9723-927c99798026:

"rptest.tests.cloud_storage_scrubber_test.CloudStorageScrubberTest.test_scrubber.cloud_storage_type=CloudStorageType.S3"

[travisdowns]

Updated as this moved to the .cc from the .h.

[vbotbuildovich]

ducktape was retried in https://buildkite.com/redpanda/redpanda/builds/47131#018e95d7-9a0c-42e2-b22a-ba3b01900abb

ducktape was retried in https://buildkite.com/redpanda/redpanda/builds/47131#018e96a1-81d5-4f4c-9509-64605948aaa4