fix(llmisvc): align customizeManagerOptions hook to return error (opendatahub-io#1374)

* fix(llmisvc): align customizeManagerOptions hook to return error

Upstream kserve#5240 changed customizeManagerOptions to return
an error, consistent with the other distro hooks (extendControllerSetup,
reconcileRouterPlatformNetworking). Aligns both the default no-op and the
OCP implementation to the updated signature, and adds error handling at the
call site in main.

* fix: precommit

---------

Signed-off-by: Bartosz Majsak <bartosz.majsak@gmail.com>

Author: bartoszmajsak

cmd/llmisvc/manager_options_ocp.go

@@ -38,6 +38,7 @@ func customizeManagerOptions(opts *ctrl.Options) error {
 		if labelSel == nil {
 			labelSel = cfg.Namespaces[cache.AllNamespaces].LabelSelector
 		}
+
 		opts.Cache.ByObject[obj] = cache.ByObject{
 			Namespaces: map[string]cache.Config{
 				llmisvc.ServiceCASigningSecretNamespace: {
@@ -50,6 +51,7 @@ func customizeManagerOptions(opts *ctrl.Options) error {
 				},
 			},
 		}
+
 		return nil
 	}