fix(webpack): Await source map deletion before signaling build completion

This PR reworks the webpack plugin to await the source map deletion before
moving on. This matches the behavior of the rollup and esbuild plugins.

Author: andreiborza

packages/webpack-plugin/src/webpack4and5.ts

@@ -277,11 +277,11 @@ export function sentryWebpackPluginFactory({
 
         compiler.hooks.afterEmit.tapAsync(
           "sentry-webpack-plugin",
-          (compilation: WebpackCompilation, callback: () => void) => {
+          (compilation: WebpackCompilation, callback: (err?: Error) => void) => {
             const freeGlobalDependencyOnBuildArtifacts = createDependencyOnBuildArtifacts();
             const upload = createDebugIdUploadFunction({ sentryBuildPluginManager });
 
-            void sentryBuildPluginManager
+            sentryBuildPluginManager
               .createRelease()
               .then(async () => {
                 if (sourcemapsEnabled && options.sourcemaps?.disable !== "disable-upload") {
@@ -292,13 +292,14 @@ export function sentryWebpackPluginFactory({
                   await upload(buildArtifacts);
                 }
               })
-              .then(() => {
-                callback();
-              })
-              .finally(() => {
+              .finally(async () => {
                 freeGlobalDependencyOnBuildArtifacts();
-                void sentryBuildPluginManager.deleteArtifacts();
-              });
+                await sentryBuildPluginManager.deleteArtifacts();
+              })
+              .then(
+                () => callback(),
+                (err: Error) => callback(err)
+              );
           }
         );