[ARO-22145] Bump FluentBit to 5.0.0 and Azure Linux 3

[rhamitarora]

Which issue this PR addresses:

Part of ARO-22145 — Migrate ARO RP/Gateway VMSS from Azure Linux 2.0 to Azure Linux 3.0.

What this PR does / why we need it:

Updates the installer-aro-wrapper to align with the Azure Linux 3 migration in ARO-RP#4766:

• Bumps FluentBit from 4.2.2 (Azure Linux 2) to 5.0.0-cm3.0.20260519 (Azure Linux 3)
• Updates the base image version to Microsoft Linux 3.0.20260519

Test plan:

• Validated on Stage and Canary environments (see ARO-22197)
• FluentBit 5.0.0 container starts and ships logs successfully on AL3 FIPS nodes

Is there any documentation that needs to be updated for this PR?

No.

How do you know this will function as expected in production?

Tested end-to-end on Stage and Canary with Azure Linux 3.0.20260519 FIPS images. Log collection via FluentBit 5.0.0 confirmed working.

[openshift-ci]

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[openshift-ci]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: preetisht, rhamitarora
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[hawkowl]

Since we're not using fluentbit in the wrapper for bootstrap logging anymore, I think we can just get rid of this const entirely now