Bump protobufjs and google-gax in /backend

Bumps [protobufjs](https://github.com/protobufjs/protobuf.js) and [google-gax](https://github.com/googleapis/gax-nodejs). These dependencies needed to be updated together.

Updates `protobufjs` from 7.2.3 to 7.2.4
- [Release notes](https://github.com/protobufjs/protobuf.js/releases)
- [Changelog](https://github.com/protobufjs/protobuf.js/blob/master/CHANGELOG.md)
- [Commits](protobufjs/protobuf.js@protobufjs-v7.2.3...protobufjs-v7.2.4)

Updates `google-gax` from 3.6.0 to 3.6.1
- [Release notes](https://github.com/googleapis/gax-nodejs/releases)
- [Changelog](https://github.com/googleapis/gax-nodejs/blob/main/release-please-config.json)
- [Commits](googleapis/gax-nodejs@v3.6.0...v3.6.1)

---
updated-dependencies:
- dependency-name: protobufjs
  dependency-type: indirect
- dependency-name: google-gax
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>

backend/yarn.lock

@@ -2247,9 +2247,9 @@ google-auth-library@^8.0.1, google-auth-library@^8.0.2:
     lru-cache "^6.0.0"
 
 google-gax@^3.5.7:
-  version "3.6.0"
-  resolved "https://registry.npmjs.org/google-gax/-/google-gax-3.6.0.tgz"
-  integrity sha512-2fyb61vWxUonHiArRNJQmE4tx5oY1ni8VPo08fzII409vDSCWG7apDX4qNOQ2GXXT82gLBn3d3P1Dydh7pWjyw==
+  version "3.6.1"
+  resolved "https://registry.yarnpkg.com/google-gax/-/google-gax-3.6.1.tgz#02c78fc496f5adf86f2ca9145545f4b6575f6118"
+  integrity sha512-g/lcUjGcB6DSw2HxgEmCDOrI/CByOwqRvsuUvNalHUK2iPPPlmAIpbMbl62u0YufGMr8zgE3JL7th6dCb1Ry+w==
   dependencies:
     "@grpc/grpc-js" "~1.8.0"
     "@grpc/proto-loader" "^0.7.0"
@@ -2263,7 +2263,7 @@ google-gax@^3.5.7:
     node-fetch "^2.6.1"
     object-hash "^3.0.0"
     proto3-json-serializer "^1.0.0"
-    protobufjs "7.2.3"
+    protobufjs "7.2.4"
     protobufjs-cli "1.1.1"
     retry-request "^5.0.0"
 
@@ -3090,10 +3090,28 @@ [email protected]:
     tmp "^0.2.1"
     uglify-js "^3.7.7"
 
-[email protected], protobufjs@^7.0.0:
-  version "7.2.3"
-  resolved "https://registry.npmjs.org/protobufjs/-/protobufjs-7.2.3.tgz"
-  integrity sha512-TtpvOqwB5Gdz/PQmOjgsrGH1nHjAQVCN7JG4A6r1sXRWESL5rNMAiRcBQlCAdKxZcAbstExQePYG8xof/JVRgg==
+[email protected]:
+  version "7.2.4"
+  resolved "https://registry.yarnpkg.com/protobufjs/-/protobufjs-7.2.4.tgz#3fc1ec0cdc89dd91aef9ba6037ba07408485c3ae"
+  integrity sha512-AT+RJgD2sH8phPmCf7OUZR8xGdcJRga4+1cOaXJ64hvcSkVhNcRHOwIxUatPH15+nj59WAGTDv3LSGZPEQbJaQ==
+  dependencies:
+    "@protobufjs/aspromise" "^1.1.2"
+    "@protobufjs/base64" "^1.1.2"
+    "@protobufjs/codegen" "^2.0.4"
+    "@protobufjs/eventemitter" "^1.1.0"
+    "@protobufjs/fetch" "^1.1.0"
+    "@protobufjs/float" "^1.0.2"
+    "@protobufjs/inquire" "^1.1.0"
+    "@protobufjs/path" "^1.1.2"
+    "@protobufjs/pool" "^1.1.0"
+    "@protobufjs/utf8" "^1.1.0"
+    "@types/node" ">=13.7.0"
+    long "^5.0.0"
+
+protobufjs@^7.0.0:
+  version "7.2.5"
+  resolved "https://registry.yarnpkg.com/protobufjs/-/protobufjs-7.2.5.tgz#45d5c57387a6d29a17aab6846dcc283f9b8e7f2d"
+  integrity sha512-gGXRSXvxQ7UiPgfw8gevrfRWcTlSbOFg+p/N+JVJEK5VhueL2miT6qTymqAmjr1Q5WbOCyJbyrk6JfWKwlFn6A==
   dependencies:
     "@protobufjs/aspromise" "^1.1.2"
     "@protobufjs/base64" "^1.1.2"