DM-45959: Update timing metrics for LoadDiaCatalogsTask

[isullivan]

{Summary of changes. Prefix PR title with JIRA issue.}

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• [ x] Do unit tests pass (scons and/or stack-os-matrix)?
• [x ] Did you run ap_verify.py on at least one of the standard datasets?
  For changes to metrics, the print_metricvalues script from lsst.verify will be useful.
• [x ] Is the Sphinx documentation up-to-date?

[kfindeisen]

Looks good, thanks for catching this!