Fix ilm config at startup (#19189)

Remove api.expiration_workers config setting which was inadvertently left behind. Per review comment 

https://github.com/minio/minio/pull/18926, expiration_workers can be configured via ilm.expiration_workers.

cmd/ilm-config.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2015-2024 MinIO, Inc.
+//
+// This file is part of MinIO Object Storage stack
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package cmd
+
+import (
+	"sync"
+
+	"github.com/minio/minio/internal/config/ilm"
+)
+
+var globalILMConfig = ilmConfig{
+	cfg: ilm.Config{
+		ExpirationWorkers: 100,
+		TransitionWorkers: 100,
+	},
+}
+
+type ilmConfig struct {
+	mu  sync.RWMutex
+	cfg ilm.Config
+}
+
+func (c *ilmConfig) getExpirationWorkers() int {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	return c.cfg.ExpirationWorkers
+}
+
+func (c *ilmConfig) getTransitionWorkers() int {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	return c.cfg.TransitionWorkers
+}
+
+func (c *ilmConfig) update(cfg ilm.Config) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+
+	c.cfg = cfg
+}