Bump grpc from 1.20.0 to 1.24.9 in /api-service/api-server
Bump grpc from 1.20.0 to 1.24.9 in /api-service/api-server

Bumps [grpc](https://github.com/grpc/grpc-node) from 1.20.0 to 1.24.9.
- [Release notes](https://github.com/grpc/grpc-node/releases)
- [Commits](https://github.com/grpc/grpc-node/commits)

Signed-off-by: dependabot[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@github.com>
conversationai/conversationai-crowdsource,conversationai/conversationai-crowdsource,conversationai/conversationai-crowdsource,conversationai/conversationai-crowdsource,conversationai/conversationai-crowdsource