DAOS-16483 vos: handle empty DTX when vos_tx_end - b26

[Nasf-Fan]

It is possible that the DTX modified nothing when stop currnet backend transaction. Under such case, we may not generate persistent DTX entry. Then need to bypass such case before checking on-disk DTX entry status.

The patch makes some clean and removed redundant metrics for committed DTX entries.

Enhance vos_dtx_deregister_record() to handle GC case.

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[github-actions]

Ticket title is 'Segmentation fault inside vos_tx_end() when handle empty DTX'
Status is 'In Progress'
https://daosio.atlassian.net/browse/DAOS-16483

[daosbuild1]

Test stage Functional Hardware Medium Verbs Provider completed with status FAILURE. https://build.hpdd.intel.com//job/daos-stack/job/daos/view/change-requests/job/PR-15055/1/execution/node/1551/log

[Nasf-Fan]

Test stage Functional Hardware Medium Verbs Provider completed with status FAILURE. https://build.hpdd.intel.com//job/daos-stack/job/daos/view/change-requests/job/PR-15055/1/execution/node/1551/log

Some PMEM hardware issue caused test CI failure, not related with the patch.

[daltonbohning]

ftest LGTM