bump fluentbit to 0.15.15-bb.0

Package Owner Merge Request

Package Changes

Fluent-bit to 1.7.9 (tag 0.15.15-bb.0)

https://repo1.dso.mil/platform-one/big-bang/apps/core/fluentbit/-/merge_requests/24

Additional Details

bumped to 1.7.9 to match the latest helm chart, no changes to bb-test-lib

Closes https://repo1.dso.mil/platform-one/big-bang/bigbang/-/issues/551