fix(build): make apt-get upgrade non-interactive in Docker builds

apt-get upgrade -y hit an interactive dpkg conffile prompt
(/etc/debian_version) when the DHI base image's base-files package
shipped a newer version, blocking on stdin in CI with no TTY to answer
it. Sets DEBIAN_FRONTEND=noninteractive and forces the existing conffile
to be kept, so an upstream base-files bump can't stall the build again.

Author: chethann007

build/knowlg-service/Dockerfile

@@ -4,8 +4,9 @@ ARG DHI_IMAGE_RUNTIME=dhi.io/eclipse-temurin:11.0.31-debian13
 FROM --platform=linux/x86_64 dhi.io/busybox:1.38.0-alpine3.24 as shell
 
 FROM --platform=linux/x86_64 ${DHI_IMAGE_DEV} AS build
-RUN apt-get update \
-    && apt-get upgrade -y \
+RUN export DEBIAN_FRONTEND=noninteractive \
+    && apt-get update \
+    && apt-get upgrade -y -o Dpkg::Options::="--force-confold" \
     && apt-get install -y unzip curl \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*

build/search-service/Dockerfile

@@ -6,8 +6,9 @@ FROM --platform=linux/x86_64 dhi.io/busybox:1.38.0-alpine3.24 as shell
 # ---- prep stage: unzip/curl need apt + root, so use the dev variant here ----
 FROM --platform=linux/x86_64 ${DHI_IMAGE_DEV} AS build
 
-RUN apt-get update \
-    && apt-get upgrade -y \
+RUN export DEBIAN_FRONTEND=noninteractive \
+    && apt-get update \
+    && apt-get upgrade -y -o Dpkg::Options::="--force-confold" \
     && apt-get install -y unzip curl \
     && apt-get clean \
     && rm -rf /var/lib/apt/lists/*