chore(deps): bump io.grpc:grpc-protobuf in /hiero-dependency-versions

Bumps [io.grpc:grpc-protobuf](https://github.com/grpc/grpc-java) from 1.68.2 to 1.69.0.
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](grpc/grpc-java@v1.68.2...v1.69.0)

---
updated-dependencies:
- dependency-name: io.grpc:grpc-protobuf
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

hiero-dependency-versions/build.gradle.kts

@@ -15,8 +15,8 @@ dependencies.constraints {
     api("com.google.protobuf:protobuf-javalite:4.29.1") { because("com.google.protobuf") }
     api("io.grpc:grpc-api:1.68.2") { because("io.grpc") }
     api("io.grpc:grpc-inprocess:1.67.1") { because("io.grpc.inprocess") }
-    api("io.grpc:grpc-protobuf:1.68.2") { because("io.grpc.protobuf") }
-    api("io.grpc:grpc-protobuf-lite:1.68.2") { because("io.grpc.protobuf.lite") }
+    api("io.grpc:grpc-protobuf:1.69.0") { because("io.grpc.protobuf") }
+    api("io.grpc:grpc-protobuf-lite:1.69.0") { because("io.grpc.protobuf.lite") }
     api("io.grpc:grpc-stub:1.68.2") { because("io.grpc.stub") }
     api("com.google.code.findbugs:jsr305:3.0.2") { because("java.annotation") }
     api("org.bouncycastle:bcpkix-jdk18on:1.79") { because("org.bouncycastle.pkix") }