Playwright Browser-Mode Fix Stops Excluded Plugins Being Updated and Triggering False Alerts

A bug in a Playwright-based WordPress maintenance tool caused plugins marked as excluded from updates to be updated anyway during browser-mode runs, including as a residual pass after SSH-based updates. The root cause was a select-all checkbox approach on WordPress's update-core.php page that never consulted the excluded plugins list. Additionally, the post-update residual check incorrectly flagged intentionally skipped plugins as pending updates, generating misleading warning emails. The fix introduces per-checkbox evaluation that extracts each plugin's slug and skips it if found in the exclusion list, mirroring the filtering already applied via WP-CLI on SSH-capable sites. A separate residual-state function was also updated so that only excluded plugins remaining on the update page no longer trigger a warning.