chore(deps): Bump io.grpc:protoc-gen-grpc-java

Bumps [io.grpc:protoc-gen-grpc-java](https://github.com/grpc/grpc-java) from 1.66.0 to 1.69.0.
- [Release notes](https://github.com/grpc/grpc-java/releases)
- [Commits](grpc/grpc-java@v1.66.0...v1.69.0)

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

Signed-off-by: dependabot[bot] <support@github.com>

pbj-core/hiero-dependency-versions/build.gradle.kts

@@ -63,7 +63,7 @@ dependencies.constraints {
     // Code generation
     api("org.antlr:antlr4:$antlr")
     api("com.google.protobuf:protoc:$protobuf")
-    api("io.grpc:protoc-gen-grpc-java:1.66.0")
+    api("io.grpc:protoc-gen-grpc-java:1.69.0")
 
     // Testing only
     api("com.google.guava:guava:33.4.0-jre") { because("com.google.common") }