Simplify handling addGrant result when granting storage access

e6b6f75589149026a96389b9a9cd875ba0cbdb43

Simplify handling addGrant result when granting storage access
https://bugs.webkit.org/show_bug.cgi?id=270208
rdar://123728856

Reviewed by NOBODY (OOPS!).

In 271821@main I added support for granting storage access for a group of
domains. This change simplifies part of that logic.

* Source/WebKit/NetworkProcess/Classifier/ResourceLoadStatisticsStore.cpp:
(WebKit::ResourceLoadStatisticsStore::grantStorageAccess):

https://github.com/WebKit/WebKit/commit/e6b6f75589149026a96389b9a9cd875ba0cbdb43

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt		✅ 🛠 gtk
	❌ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

EWS run on previous version of this PR (hash https://github.com/WebKit/WebKit/commit/c3329f0ea31c0d13c555f97114a2a0e6ee90dba7)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	~~🧪 wpe-wk2~~
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	~~🧪 api-wpe~~
	✅ 🧪 ios-wk2-wpt		✅ 🛠 gtk
	✅ 🧪 api-ios	✅ 🧪 mac-wk2	❌ 🧪 gtk-wk2
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim
	✅ 🛠 watch
	✅ 🛠 watch-sim

EWS run on current version of this PR (hash https://github.com/WebKit/WebKit/commit/e6b6f75589149026a96389b9a9cd875ba0cbdb43)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 wincairo
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe
	✅ 🧪 ios-wk2-wpt		✅ 🛠 gtk
	❌ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🧪 gtk-wk2
	✅ 🛠 tv	✅ 🧪 mac-AS-debug-wk2	✅ 🧪 api-gtk
	✅ 🛠 tv-sim
✅ 🛠 🧪 merge	✅ 🛠 watch
	✅ 🛠 watch-sim

Failed api-ios checks. Please resolve failures and re-apply safe-merge-queue label.

Rejecting #25262 from merge queue.

Safe-Merge-Queue: Build #13633.

Committed 275572@main (4caf2bb34aab): https://commits.webkit.org/275572@main

Reviewed commits have been landed. Closing PR #25262 and removing active labels.