PADV-1341: Improve LTI AGS score publish code

[kuipumu]

Tickets

• https://agile-jira.pearson.com/browse/PADV-1341

Description

This PR adds various improvements to the LTI AGS score publish code, more specifically to the code responsible of sending the request to the LTI platform AGS score publish service endpoint and the code responsible for sending score updates for LTI launches using the LTI AGS service on graded courses.

Type of Change

• Rename the signal receiver update_course_score to publish_course_score.
• Remove unnecesary code from the publish_course_score receiver.
• Add logging to publish_course_score receiver.
• Rename update_score method from LtiGradedResource model to publish_score.
• Add try/except block to LTI AGS publish score request.
• Add logging to the publish_score method.
• Add or modify any unit test for all related code.