Fix race condition in the web package (#29288)

Essentially applying the fix for https://github.com/mattermost/mattermost/pull/29214
to the web package. It seems like the app.StoreOverrideWithCache
function was never used in this package.

Just a small highlight of how much boilerplate is repeated
in multiple packages
```release-note
NONE
```

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/web/web_test.go

@@ -23,7 +23,6 @@ import (
 	"github.com/mattermost/mattermost/server/public/shared/mlog"
 	"github.com/mattermost/mattermost/server/public/shared/request"
 	"github.com/mattermost/mattermost/server/v8/channels/app"
-	"github.com/mattermost/mattermost/server/v8/channels/store/localcachelayer"
 	"github.com/mattermost/mattermost/server/v8/channels/store/storetest/mocks"
 	"github.com/mattermost/mattermost/server/v8/config"
 )
@@ -83,7 +82,12 @@ func setupTestHelper(tb testing.TB, includeCacheLayer bool, options []app.Option
 	*newConfig.LogSettings.ConsoleLevel = mlog.LvlStdLog.Name
 	memoryStore.Set(newConfig)
 	options = append(options, app.ConfigStore(memoryStore))
-	options = append(options, app.StoreOverride(mainHelper.Store))
+	if includeCacheLayer {
+		// Adds the cache layer to the test store
+		options = append(options, app.StoreOverrideWithCache(mainHelper.Store))
+	} else {
+		options = append(options, app.StoreOverride(mainHelper.Store))
+	}
 
 	testLogger, _ := mlog.NewLogger()
 	logCfg, _ := config.MloggerConfigFromLoggerConfig(&newConfig.LogSettings, nil, config.GetLogFileLocation)
@@ -98,15 +102,6 @@ func setupTestHelper(tb testing.TB, includeCacheLayer bool, options []app.Option
 	if err != nil {
 		panic(err)
 	}
-	if includeCacheLayer {
-		// Adds the cache layer to the test store
-		var st localcachelayer.LocalCacheStore
-		st, err = localcachelayer.NewLocalCacheLayer(s.Store(), s.GetMetrics(), s.Platform().Cluster(), s.Platform().CacheProvider(), testLogger)
-		if err != nil {
-			panic(err)
-		}
-		s.SetStore(st)
-	}
 
 	a := app.New(app.ServerConnector(s.Channels()))
 	prevListenAddress := *s.Config().ServiceSettings.ListenAddress