Move deprecate-unload flag to the deprecated flags section.

(cherry picked from commit d08e2c0)

Bug: 1432116,1472288
Change-Id: If363270b971584cc7c4717805d137cfeed04152c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4764528
Auto-Submit: Fergal Daly <fergal@chromium.org>
Commit-Queue: Owen Min <zmin@chromium.org>
Reviewed-by: Owen Min <zmin@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1182184}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4779739
Commit-Queue: Prudhvikumar Bommana <pbommana@google.com>
Owners-Override: Prudhvikumar Bommana <pbommana@google.com>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Auto-Submit: Prudhvikumar Bommana <pbommana@google.com>
Cr-Commit-Position: refs/branch-heads/5938@{chromium#145}
Cr-Branched-From: 2b50cb4-refs/heads/main@{#1181205}

chrome/browser/about_flags.cc

@@ -10816,7 +10816,7 @@ const FeatureEntry kFeatureEntries[] = {
      STRING_VALUE_TYPE(switches::kProtectedAudiencesConsentedDebugToken, "")},
 
     {"deprecate-unload", flag_descriptions::kDeprecateUnloadName,
-     flag_descriptions::kDeprecateUnloadDescription, kOsAll,
+     flag_descriptions::kDeprecateUnloadDescription, kOsAll | kDeprecated,
      FEATURE_VALUE_TYPE(blink::features::kDeprecateUnload)},
 
     {"autofill-enable-fpan-risk-based-authentication",