Removed credentials from set_result event handlers

[a-velasco]

Issue

Credentials get printed to the terminal in plaintext when using s3-integrator. This causes a security issue during demos and video recordings.

(see DPE-3198 for more details)

Solution

Update event handlers/observers that print the credentials.

• Functions handling secrets (e.g. _on_sync_s3_credentials() will instead display a message related to the action (e.g. "Credentials successfully updated")
• Functions that print other parameters along with secrets (i.e. on_get_connection_info_action() will replace the secrets with asterisks.