Fix interactive task form resubmission after error and improve task completion check

[ilicfilip]

Interactive task form listener (assets/js/recommendations/interactive-task.js)

• Moved form listener removal from finally block to popover toggle event
• Previously, the listener was removed after every submission attempt, preventing users from resubmitting after an error
• Now the listener is removed only when the popover closes

Set valuable post types provider (classes/suggested-tasks/providers/class-set-valuable-post-types.php)

• Changed should_add_task() to check activities table instead of task post existence
• Aligns with the pattern used by set-date-format, select-timezone, and select-locale providers
• Activities are a more reliable source of truth as they persist even if task posts are deleted

[github-actions]

Test merged PR on Playground
Test this pull request on the Playground
or download the zip

[github-actions]

✅ Code Coverage Report

Metric	Value
Total Coverage	31.60% 📉
Base Coverage	31.60%
Difference	📈 0.00%

⚠️ Coverage below recommended 40% threshold

🎉 Great job maintaining/improving code coverage!

ℹ️ About this report

• All tests run in a single job with Xdebug coverage
• Security tests excluded from coverage to prevent output issues
• Coverage calculated from line coverage percentages