[M116] Use weak_ptr in ambient badge GetClassificationResult callback

(cherry picked from commit 75b079d)

Bug: 1458010
Change-Id: Ibb7b3cd93dd3c066ba893a772e4b40e93a79c774
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4666080
Auto-Submit: Ella Ge <eirage@chromium.org>
Reviewed-by: Siddhartha S <ssid@chromium.org>
Commit-Queue: Siddhartha S <ssid@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1165729}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4663777
Cr-Commit-Position: refs/branch-heads/5845@{#344}
Cr-Branched-From: 5a5dff6-refs/heads/main@{#1160321}

components/webapps/browser/android/ambient_badge_manager.cc

@@ -244,7 +244,7 @@ void AmbientBadgeManager::MaybeShowAmbientBadgeSmart(
       segmentation_platform::kWebAppInstallationPromoKey, prediction_options,
       input_context,
       base::BindOnce(&AmbientBadgeManager::OnGotClassificationResult,
-                     base::Unretained(this)));
+                     weak_factory_.GetWeakPtr()));
 }
 
 void AmbientBadgeManager::OnGotClassificationResult(