Pending event confirmation and receipt - should get sent after contribution status is set to completede

Confirmation should be sent only when the contribution (related to a participant) status changes to Completed from Pending. The confirmation should include event details when it is sent.

Current incorrect behavior is:

• a receipt is sent with blank transactionID and credit card details, even if an event is registered using "pay later" option.
• a second receipt is sent when the admin records the received payment by updating contribution status to Completed. However this receipt is missing the associated event info

Please test this flow for Membership / Pay Later as well as Contribution.
Please verify that the correct receipt / confirmation is sent when using the Update Pending Contribution Status action from Find Contributions.