Update google-protobuf and remove workaround

In order to comply with the no-unsafe-eval CSP, we worked around issue
https://github.com/protocolbuffers/protobuf/issues/6770 by including a
modified version of google-protobuf under the src/third_party folder.

This CL updates the google-protobuf version to one which fixes this bug,
and removes the workaround.

Change-Id: Ida7943bad452ee930defbc136602a34910a41977
diff --git a/Makefile b/Makefile
index 44c40a2..bf2a1e2 100644
--- a/Makefile
+++ b/Makefile
@@ -8,9 +8,7 @@
 	(cd src/killSwitch && \
 		protoc -I=. --js_out=import_style=commonjs_strict:. api_proto/*.proto && \
-		protoc -I. --grpc-web_out=import_style=commonjs,mode=grpcwebtext:. api_proto/*.proto && \
-		(cd api_proto && \
-			sed -i -E "s/require\('google-protobuf\//require('..\/..\/third_party\/google-protobuf-commonjs_strict\//" *_pb.js ))
+		protoc -I. --grpc-web_out=import_style=commonjs,mode=grpcwebtext:. api_proto/*.proto)
 	npm ci --no-save