tests: Update the vendored protobuf conformance protos to 33.4

The protos were taken from 21.9, many releases behind the suite. Track
the release the vcpkg protobuf port builds, so they match the protoc and
libprotobuf qtgrpc links against.

The protos are independent of conformance_test_runner and only have to
cover the messages the runner drives, so one copy serves both a current
runner and the 21.9 one the CI images still carry.

[ChangeLog][Third-Party Code] The vendored protobuf conformance test
protos were updated to protobuf 33.4.

Task-number: QTBUG-150055
Pick-to: 6.12
Change-Id: I7efd8b1006152d914633a08cf05668e1e3ce165b
Reviewed-by: Tatiana Borisova <tatiana.borisova@qt.io>