add well known type support to doc service autocomplete

[Dogacel]

Motivation:

JSON hints for WKTs were incorrect, this was especially annoying for me considering timestamps are pretty common in our codebase.

https://protobuf.dev/programming-guides/proto3/#json

Note:

• Add support to export flat json schemas #4844
  needs to be merged first.

Modifications:

• Update JSON schema generator to return correct type and properties for WKTs.

Result:

• Fix Protobuf WKT JSON schema being incorrectly generated.

[github-actions]

🔍 Build Scan® (commit: 51da5f5)

Job name	Status	Build Scan®
build-windows-latest-jdk-19	✅	https://ge.armeria.dev/s/atcw3fc4lwaju
build-self-hosted-unsafe-jdk-8	✅	https://ge.armeria.dev/s/bzzkamvd22oa6
build-self-hosted-unsafe-jdk-19-snapshot-blockhound	✅	https://ge.armeria.dev/s/kxlnz4p3itunw
build-self-hosted-unsafe-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/mejpfcdubnwjq
build-self-hosted-unsafe-jdk-17-min-java-11	✅	https://ge.armeria.dev/s/yhifpevrjzqii
build-self-hosted-unsafe-jdk-17-leak	✅	https://ge.armeria.dev/s/kp4vhup2pl4ru
build-self-hosted-unsafe-jdk-11	✅	https://ge.armeria.dev/s/6r34eks3mcqfu
build-macos-12-jdk-19	✅	https://ge.armeria.dev/s/hgnfhthyjqdmm