This commit updates the ad plugin to support the Glimmer Post Stream and refactors ad rendering logic for improved compatibility and maintainability.
Key changes:
- Introduce glimmer_post_stream_mode compatibility across all ad types and test suites.
- Replace .widget-connector with .ad-connector for ad placement after posts.
- Migrate initialize-ad-plugin.js to initialize-ad-plugin.gjs to leverage Glimmer and API improvements.
- Use withSilencedDeprecations to handle widget overrides for post ads.
- Update compatibility constraints in .discourse-compatibility.
- Refactor and expand acceptance tests for AdSense, DFP, and House Ads to run with both Glimmer and legacy post stream modes.
