Updated flag expiration milestones

Updated flag expiration milestones for two experiments
1 - download-auto-resumption-native
2 - enable-new-download-backend

Change-Id: If5ab4573e06843767f8387e5cea95d218dc84ba6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2008625Reviewed-by: Shakti Sahu <shaktisahu@chromium.org>
Reviewed-by: Hesen Zhang <hesen@chromium.org>
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733533}

chrome/browser/flag-metadata.json

@@ -859,7 +859,7 @@
   {
     "name": "download-auto-resumption-native",
     "owners": [ "shaktisahu", "qinmin" ],
-    "expiry_milestone": 80
+    "expiry_milestone": 86
   },
   {
     "name": "draw-vertically-edge-to-edge",
@@ -1603,7 +1603,7 @@
   {
     "name": "enable-new-download-backend",
     "owners": [ "shaktisahu", "dtrainor" ],
-    "expiry_milestone": 80
+    "expiry_milestone": 86
   },
   {
     "name": "enable-noscript-previews",