DAOS-16687 control: Handle missing PCIe caps in storage query usage

[tanabarr]

Missing PCIe capabilities when querying a NVMe SSD's configuration
space is unusual but should be handled gracefully by the control-plane
and shouldn't cause a failure to return usage statistics when calling
dmg storage query usage.

Update so that pciutils lib is only called when attempting to display
health stats via dmg and not when fetching usage info. Improve clarity
of workflow to ease maintenance and add test coverage for updates.
Enable continued functionality when NVMe device doesn't return any
extended capabilities in PCIe configuration space data by adding
sentinel error to library for such a case.

Features: control
Required-githooks: true

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[github-actions]

Ticket title is 'dmg storage query usage fails if no PCIe capabilities'
Status is 'In Review'
https://daosio.atlassian.net/browse/DAOS-16687

[daosbuild1]

Test stage Functional Hardware Medium completed with status FAILURE. https://build.hpdd.intel.com//job/daos-stack/job/daos/view/change-requests/job/PR-15296/2/execution/node/1431/log

[knard38]

LGTM for what I understand.

[kjacque]

Good fixes, thanks. The one issue remaining open for me is the assumption about the interaction between the incoming flags (meta vs. health). IMO needing to make an assumption like that is a sign that we need more granular flags coming in.