Use newer multiarch support for DRA packaging in ARM #6948 (#6951)

This commit fixes a recent problem where the packaging ARM step
started failing after upgrading go from 1.22 to 1.23.

It does so by:
- switching to Ubuntu 22.04 ARM for the ARM part of the DRA packaging
- enabling multi arch builds using a similar approach to elastic/golang-crossbuild#507

(cherry picked from commit 93cfb49)

Co-authored-by: Dimitrios Liappis <dimitrios.liappis@gmail.com>

.buildkite/pipeline.elastic-agent-package.yml

@@ -79,11 +79,14 @@ steps:
         agents:
           provider: "aws"
           instanceType: "t4g.2xlarge"
-          imagePrefix: "core-ubuntu-2004-aarch64"
+          imagePrefix: "core-ubuntu-2204-aarch64"
         env:
           PLATFORMS: "linux/arm64"
           PACKAGES: "docker"
         command: |
+          echo "Add support for multiarch"
+          docker run --privileged --rm tonistiigi/binfmt:master --install all
+
           if [[ -z "$${MANIFEST_URL}" ]]; then
             export MANIFEST_URL=$(buildkite-agent meta-data get MANIFEST_URL --default "")
             if [[ -z "$${MANIFEST_URL}" ]]; then
@@ -110,10 +113,10 @@ steps:
       DRA_PROJECT_ARTIFACT_ID: "agent-package"
     command: |
       echo "+++ Restoring Artifacts"
-      buildkite-agent artifact download "build/**/*" . 
+      buildkite-agent artifact download "build/**/*" .
 
-      echo "+++ Changing permissions for the release manager"      
-      sudo chmod -R a+r build/distributions/ 
+      echo "+++ Changing permissions for the release manager"
+      sudo chmod -R a+r build/distributions/
       sudo chown -R :1000 build/distributions/
       ls -lahR build/