[SPARK-30111][K8S] Apt-get update to fix debian issues

### What changes were proposed in this pull request?
Added apt-get update as per [docker best-practices](https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#apt-get)

### Why are the changes needed?
Builder is failing because:
Without doing apt-get update, the APT lists get outdated and begins referring to package versions that no longer exist, hence the 404 trying to download them (Debian does not keep old versions in the archive when a package is updated).

### Does this PR introduce any user-facing change?
no

### How was this patch tested?
k8s builder

Closes apache#26753 from ifilonenko/SPARK-30111.

Authored-by: Ilan Filonenko <[email protected]>
Signed-off-by: shane knapp <[email protected]>

Author: ifilonenko

resource-managers/kubernetes/docker/src/main/dockerfiles/spark/bindings/R/Dockerfile

@@ -25,7 +25,7 @@ USER 0
 
 RUN mkdir ${SPARK_HOME}/R
 
-RUN apt install -y r-base r-base-dev && rm -rf /var/cache/apt/*
+RUN apt-get update && apt install -y r-base r-base-dev && rm -rf /var/cache/apt/*
 
 COPY R ${SPARK_HOME}/R
 ENV R_HOME /usr/lib/R

resource-managers/kubernetes/docker/src/main/dockerfiles/spark/bindings/python/Dockerfile

@@ -25,7 +25,8 @@ USER 0
 
 RUN mkdir ${SPARK_HOME}/python
 # TODO: Investigate running both pip and pip3 via virtualenvs
-RUN apt install -y python python-pip && \
+RUN apt-get update && \
+    apt install -y python python-pip && \
     apt install -y python3 python3-pip && \
     # We remove ensurepip since it adds no functionality since pip is
     # installed on the image and it just takes up 1.6MB on the image