Update Ironbank to v1.17.6

This MR contains the following updates:

Package	Update	Change
ironbank/hashicorp/vault (source)	patch	1.17.5 -> 1.17.6
registry1.dso.mil/ironbank/hashicorp/vault (source)	patch	1.17.5 -> 1.17.6

Complete MR checklist

Assignee

• Followed upgrade instructions outlined in docs/DEVELOPMENT_MAINTENANCE.md
• Update Docs with new/updated steps as needed
• Tested and Validated Changes made with supporting info like logs or screenshots from test pipelines

Add supporting info below

Reviewer only

• Tested and Validated changes

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Configuration

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This MR was automatically generated by Renovate Bot.

Upgrade Notices

N/A