fix(packager): wait for artifactCreated completion event before starting an upload (#6625)

When the configuration has an artifactBuildCompleted callback that is a Promise, the upload starts anyway as it listens to the artifactCreated event. This resolves that by first waiting for any hooks, then dispatching the event.

Author: DanielMcAssey

.changeset/angry-starfishes-divide.md

@@ -0,0 +1,5 @@
+---
+"app-builder-lib": patch
+---
+
+fix(packager): wait for event before starting an upload

packages/app-builder-lib/src/packager.ts

@@ -271,12 +271,12 @@ export class Packager {
   }
 
   async callArtifactBuildCompleted(event: ArtifactCreated): Promise<void> {
-    this.dispatchArtifactCreated(event)
-
     const handler = resolveFunction(this.config.artifactBuildCompleted, "artifactBuildCompleted")
     if (handler != null) {
       await Promise.resolve(handler(event))
     }
+    
+    this.dispatchArtifactCreated(event)
   }
 
   async callAppxManifestCreated(path: string): Promise<void> {