[build arm] fix sonic-slave-buster build break

When building the sonic-slave-buster docker container, the node.js package is
installed to meet the requirements of the Azure DevOPs pipleline
build. Recently this install of node.js has been failing as described within
Sonic issue sonic-net#6445. This commit fixes that build break by upgrading the
sonic-slave-buster build to install version 14.x of node.js which is the
current LTS version for buster.

sonic-slave-buster/Dockerfile.j2

@@ -484,7 +484,8 @@ RUN pip3 install git+https://github.com/aristanetworks/swi-tools.git@bead66bf261
 
 {% if CONFIGURED_ARCH != "amd64" -%}
 # Install node.js for azure pipeline
-RUN apt-get install -y node.js
+RUN curl -sL https://deb.nodesource.com/setup_14.x | bash -
+RUN apt-get install -y nodejs
 
 # Tell azure pipeline to use node.js in the docker
 LABEL "com.azure.dev.pipelines.agent.handler.node.path"="/usr/bin/node"