Avoid warning for system setting when start up (#23054)

Partially fix #23050

After #22294 merged, it always has a warning log like `cannot get
context cache` when starting up. This should not affect any real life
but it's annoying. This PR will fix the problem. That means when
starting up, getting the system settings will not try from the cache but
will read from the database directly.

---------

Co-authored-by: Lauris BH <lauris@nix.lv>

models/avatars/avatar.go

@@ -153,7 +153,7 @@ func generateEmailAvatarLink(ctx context.Context, email string, size int, final
 		return DefaultAvatarLink()
 	}
 
-	enableFederatedAvatar := system_model.GetSettingBool(ctx, system_model.KeyPictureEnableFederatedAvatar)
+	enableFederatedAvatar := system_model.GetSettingWithCacheBool(ctx, system_model.KeyPictureEnableFederatedAvatar)
 
 	var err error
 	if enableFederatedAvatar && system_model.LibravatarService != nil {
@@ -174,7 +174,7 @@ func generateEmailAvatarLink(ctx context.Context, email string, size int, final
 		return urlStr
 	}
 
-	disableGravatar := system_model.GetSettingBool(ctx, system_model.KeyPictureDisableGravatar)
+	disableGravatar := system_model.GetSettingWithCacheBool(ctx, system_model.KeyPictureDisableGravatar)
 	if !disableGravatar {
 		// copy GravatarSourceURL, because we will modify its Path.
 		avatarURLCopy := *system_model.GravatarSourceURL

models/avatars/avatar_test.go

@@ -28,7 +28,7 @@ func enableGravatar(t *testing.T) {
 	err := system_model.SetSettingNoVersion(db.DefaultContext, system_model.KeyPictureDisableGravatar, "false")
 	assert.NoError(t, err)
 	setting.GravatarSource = gravatarSource
-	err = system_model.Init()
+	err = system_model.Init(db.DefaultContext)
 	assert.NoError(t, err)
 }