refactor(notification): use new queue package (#9360)

# Which Problems Are Solved

The recently introduced notification queue have potential race conditions.

# How the Problems Are Solved

Current code is refactored to use the queue package, which is safe in
regards of concurrency.

# Additional Changes

- the queue is included in startup
- improved code quality of queue

# Additional Context

- closes https://github.com/zitadel/zitadel/issues/9278

internal/notification/messages/form.go

@@ -12,8 +12,8 @@ import (
 var _ channels.Message = (*Form)(nil)
 
 type Form struct {
-	Serializable    any
-	TriggeringEvent eventstore.Event
+	Serializable        any
+	TriggeringEventType eventstore.EventType
 }
 
 func (msg *Form) GetContent() (string, error) {
@@ -22,6 +22,6 @@ func (msg *Form) GetContent() (string, error) {
 	return values.Encode(), err
 }
 
-func (msg *Form) GetTriggeringEvent() eventstore.Event {
-	return msg.TriggeringEvent
+func (msg *Form) GetTriggeringEventType() eventstore.EventType {
+	return msg.TriggeringEventType
 }