Update Fluentbit to 1.8.6

New IB image available.

Make sure to pull in any upstream chart updates (if applicable).

Definition of done:

• Image version(s) updated in chart/values.yaml
• Chart version bumped (match upstream chart, reset to bb.0 if the upstream version changes)
• Changelog entry added, note the update to image, any additional updates
• Clean install tested and validated working (see things to test)
• Upgrade tested and validated working (install newest tagged release, upgrade to your branch, then run through things to test)
• Pipeline passing on package MR
• Package MR merged and new release tagged
• BB MR opened, pipeline passing
• BB MR merged (no checkbox, BB MR should auto-close this)

Things to test:

• Install BB with core enabled
• Validate all pods come up healthy
• Validate that logs are being passed to elastic/kibana (for the upgrade ensure logs come in post-upgrade in addition to the ones already there)