chore(deps): Update gapic-generator-java to 2.16.0 (#1683)

* chore(deps): Update gapic-generator-java to 2.16.0

PiperOrigin-RevId: 520153493

Source-Link: googleapis/googleapis@26a424a

Source-Link: https://github.com/googleapis/googleapis-gen/commit/78f1567661df07bea7425e4341012e7b77c11254
Copy-Tag: eyJwIjoiLmdpdGh1Yi8uT3dsQm90LnlhbWwiLCJoIjoiNzhmMTU2NzY2MWRmMDdiZWE3NDI1ZTQzNDEwMTJlN2I3N2MxMTI1NCJ9

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

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Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: gcf-owl-bot[bot]