[MM-64686] Expose audit logging functionality via plugin API (#31204)

This commit exposes audit logging functionality to plugins via the plugin API, allowing plugins to create and log audit records. Additionally, it addresses a gob encoding issue that could cause plugin crashes when audit data contains nil pointers or unregistered types.

server/channels/app/session.go

@@ -15,7 +15,6 @@ import (
 	"github.com/mattermost/mattermost/server/public/shared/request"
 	"github.com/mattermost/mattermost/server/v8/channels/app/platform"
 	"github.com/mattermost/mattermost/server/v8/channels/app/users"
-	"github.com/mattermost/mattermost/server/v8/channels/audit"
 	"github.com/mattermost/mattermost/server/v8/channels/store"
 )
 
@@ -346,7 +345,7 @@ func (a *App) ExtendSessionExpiryIfNeeded(rctx request.CTX, session *model.Sessi
 		return false
 	}
 
-	auditRec := a.MakeAuditRecord(rctx, "extendSessionExpiry", audit.Fail)
+	auditRec := a.MakeAuditRecord(rctx, "extendSessionExpiry", model.AuditStatusFail)
 	defer a.LogAuditRec(rctx, auditRec, nil)
 	auditRec.AddEventPriorState(session)