fix(powershell): bump Az.Accounts/Az.Resources floor in hub module manifest

[Michael Flanakin (flanakin)]

Summary

Fixes #945. The generated FinOpsToolkit PowerShell module manifest (built by .build/BuildHelper/Build-PsModule.ps1) declares a RequiredModules floor of Az.Accounts 2.17.0 / Az.Resources 6.5.1. This is what New-FinOpsCostExport, Deploy-FinOpsHub, and the other FinOps toolkit deployment cmdlets depend on — and it's well behind what's actually installed/tested today, which is the source of the stale Az PowerShell version warning reported in #945.

This PR raises the floor to Az.Accounts 5.4.0 / Az.Resources 9.1.0 — the exact versions installed and genuinely testable in this environment (not a speculative bump to some newer, untested version).

Scope note: per prior discussion on this issue (see #2250, which was rejected as off-target), this change touches only the FinOps hub PowerShell deployment surface. It does not touch CI workflow pins or the Optimization Engine.

Cmdlets validated (touch Az.Accounts/Az.Resources)

• Private/Invoke-Rest.ps1 — Get-AzAccessToken, Get-AzContext
• Private/Save-FinOpsHubTemplate.ps1 — Get-AzContext
• Public/Add-FinOpsHubScope.ps1 — Get-AzResource
• Public/Add-FinOpsServicePrincipal.ps1 — Get-AzContext
• Public/Deploy-FinOpsHub.ps1 — Get-AzResourceGroup, New-AzResourceGroup, New-AzResourceGroupDeployment
• Public/Get-FinOpsCostExport.ps1 — Get-AzContext
• Public/Get-FinOpsHub.ps1 — Get-AzContext, Get-AzResource
• Public/New-FinOpsCostExport.ps1 — Get-AzContext, Get-AzResourceProvider
• Public/Register-FinOpsHubProviders.ps1 — Get-AzResourceProvider
• Public/Remove-FinOpsCostExport.ps1 — Get-AzContext
• Public/Remove-FinOpsHub.ps1 — Get-AzContext, Get-AzResource, Remove-AzResource
• Public/Remove-FinOpsHubScope.ps1 — Get-AzResource
• Public/Start-FinOpsCostExport.ps1 — Get-AzContext

Validation (differential, before/after)

Ran the full Unit + Lint Pester suite (./src/scripts/Test-PowerShell.ps1 -Unit -Lint) against Az.Accounts 5.4.0 / Az.Resources 9.1.0 (the actually-installed versions), once on unmodified HEAD (baseline) and once with this change applied.

	Passed	Failed	Skipped
Baseline (before)	5597	2	119
After (this change)	5597	2	119

The 2 failures are identical in both runs (Should checkout the PR branch, Should use changed-files action in Action.UpdateMsLearnDates.Tests.ps1) — pre-existing, unrelated to Az.Accounts/Az.Resources, and out of scope for this fix.

Also confirmed the module builds cleanly against the new floor (Build-PsModule generates a manifest with the updated RequiredModules).

Integration tests were not run — they require live Azure authentication (Connect-AzAccount) that isn't available in this environment, so they're out of scope for this validation pass.

Test plan

• Baseline Unit+Lint run on unmodified branch: 5597 passed / 2 failed / 119 skipped
• Post-change Unit+Lint run: 5597 passed / 2 failed / 119 skipped (identical, zero regressions)
• Module builds and generates manifest with updated RequiredModules
• Integration tests (out of scope here — requires live Azure credentials)

🤖 Generated with Claude Code

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