test: new weldr client compatibility for test scripts

- Handle the array responses from the new weldr-client (>= 35.6).
- Move the `get_build_info` function to shared_libs.sh to source and
  reuse in multiple places.

test/data/upgrade8to9/upgrade_verify.sh

@@ -2,6 +2,8 @@
 
 set -euxo pipefail
 
+source /usr/libexec/tests/osbuild-composer/shared_lib.sh
+
 WORKSPACE=$(mktemp -d)
 function cleanup() {
     echo "== Script execution stopped or finished - Cleaning up =="
@@ -9,15 +11,6 @@ function cleanup() {
 }
 trap cleanup EXIT
 
-function get_build_info() {
-    key="$1"
-    fname="$2"
-    if rpm -q --quiet weldr-client; then
-        key=".body${key}"
-    fi
-    jq -r "${key}" "${fname}"
-}
-
 # Get the compose log.
 get_compose_log () {
     COMPOSE_ID=$1