Run build before integration test

I'm not sure why this was implicitly running a build before... Let's
make it explicit since a minor change to the Makefile caused the
implicit run of the build target to go away and break CI.

We don't make it a hard dependency in the Makefile because this lets you
iterate on just the test without doing a full rebuild inbetween.

build/azure-pipelines.pr-manual.yml

@@ -43,6 +43,11 @@ jobs:
     inputs:
       secureFile: kubeconfig
 
+  - script: |
+      make build
+    workingDirectory: '$(System.DefaultWorkingDirectory)'
+    displayName: 'Build'
+
   - script: |
       export KUBECONFIG=$DOWNLOADSECUREFILE_SECUREFILEPATH
       make test-integration