Extend test GenerateName support to Unstructureds

[scothis]

Unstructured resources do not implement ObjectMetaAccessor, we should cast the object to metav1.Object instead.

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.11% :tada:

Comparison is base (5be8c31) 60.62% compared to head (b3065a7) 60.73%.

:exclamation: Current head b3065a7 differs from pull request most recent head 2c1bed2. Consider uploading reports for the commit 2c1bed2 to get more accurate results

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #420 +/- ## ========================================== + Coverage 60.62% 60.73% +0.11% ========================================== Files 24 24 Lines 2334 2333 -1 ========================================== + Hits 1415 1417 +2 + Misses 835 833 -2 + Partials 84 83 -1 ``` | [Files Changed](https://app.codecov.io/gh/vmware-labs/reconciler-runtime/pull/420?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=vmware-labs) | Coverage Δ | | |---|---|---| | [testing/client.go](https://app.codecov.io/gh/vmware-labs/reconciler-runtime/pull/420?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=vmware-labs#diff-dGVzdGluZy9jbGllbnQuZ28=) | `55.12% <100.00%> (+1.08%)` | :arrow_up: |

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