Update fledge-tester-list.md (#797)

Update Testing Time Frame of SMN

fledge-tester-list.md

@@ -49,7 +49,7 @@ The usefulness of this page depends on testers sharing information and updates.
 | NextRoll | DSP | 2024-01-30 | coming soon | [email protected] |
 | OpenX | SSP | Limited testing in progress | | [email protected] |
 | RTB House | DSP | Continuous testing ongoing; long term commitment. | https://blog.rtbhouse.com/whitepaper-deep-insights-from-early-fledge-experiments/ | [email protected] |
-| SMN | DSP | | | [email protected] |
+| SMN | DSP | no later than January 31, 2024 | | [email protected] |
 | Raptive | Testing as DSP & SSP & Ad management service | ongoing | | [email protected] |
 | CyberAgent(Dynalyst) | DSP | | | [email protected] |
 | Google Ad Manager + AdSense (including with Authorized Buyers) | SSP | Testing ongoing | [Publishers (Ad Manager)](https://support.google.com/admanager/answer/12052605?hl=en) <br/> [Publishers (AdSense)](https://support.google.com/adsense/answer/12570693)  <br/> [Authorized Buyers (DSPs)](https://developers.google.com/authorized-buyers/rtb/fledge-origin-trial#onboarding) <br/> [Multi-seller auction support](https://github.com/google/ads-privacy/tree/master/proposals/fledge-multiple-seller-testing) | Publishers with questions should reach out via their account manager directly, or via our [support channels](https://support.google.com/admanager/gethelp).<br/><br/>Authorized Buyers (DSPs) interested in testing should follow the steps listed in the [onboarding guide](https://developers.google.com/authorized-buyers/rtb/fledge-origin-trial#onboarding).<br/><br/>For technical questions on the experimental GPT API for multi-seller auctions, reach out via the “send feedback” button on the [GPT developer site](https://developers.google.com/publisher-tag/reference).|