[build/canvas] Fix runtime generation (#137972) (#138029)

This fixes an issue with the CI stats plugin using `tapAsync` instead of
`tapPromise`.  It appears that if callback() is not called in
`tapAsync`, the entrypoint is not written to disk.

Co-authored-by: Kibana Machine <[email protected]>
(cherry picked from commit af58ee8)

Co-authored-by: Jonathan Budzenski <[email protected]>

x-pack/plugins/canvas/shareable_runtime/webpack/ci_stats_plugin.ts

@@ -41,7 +41,7 @@ export class CiStatsPlugin {
       return;
     }
 
-    compiler.hooks.emit.tapAsync('CiStatsPlugin', async (compilation) => {
+    compiler.hooks.emit.tapPromise('CiStatsPlugin', async (compilation) => {
       const { entryName } = this.options;
 
       const assets = Object.entries(compilation.assets)