Move deprecate-unload flag to the deprecated flags section.

Bug: 1432116
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-Commit-Position: refs/heads/main@{#1182184}

chrome/browser/about_flags.cc

@@ -10800,7 +10800,7 @@ 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",