VAULT-23468: Bill on number of secrets currently being synced (#25069)

* first pass

* launch correctly and add tests

vault/activity_log.go

@@ -1454,6 +1454,7 @@ func (c *Core) ResetActivityLog() []*activity.LogFragment {
 
 	allFragments = append(allFragments, a.standbyFragmentsReceived...)
 	a.standbyFragmentsReceived = make([]*activity.LogFragment, 0)
+	a.partialMonthClientTracker = make(map[string]*activity.EntityRecord)
 	a.fragmentLock.Unlock()
 	return allFragments
 }

vault/core.go

@@ -2816,6 +2816,11 @@ func (c *Core) postUnseal(ctx context.Context, ctxCancelFunc context.CancelFunc,
 	if c.systemBackend != nil && c.systemBackend.mfaBackend != nil {
 		c.systemBackend.mfaBackend.usedCodes = cache.New(0, 30*time.Second)
 	}
+	if c.systemBackend != nil {
+		// all mounts need to be initialized before activity log reporting
+		// starts, which happens in the post-unseal functions above.
+		sysActivityLogReporting(c.systemBackend)
+	}
 	c.logger.Info("post-unseal setup complete")
 	return nil
 }

vault/logical_system_helpers.go

@@ -39,6 +39,8 @@ var (
 		return nil
 	}
 
+	sysActivityLogReporting = func(b *SystemBackend) {}
+
 	getSystemSchemas = func() []func() *memdb.TableSchema { return nil }
 
 	getEGPListResponseKeyInfo = func(*SystemBackend, *namespace.Namespace) map[string]interface{} { return nil }