signature now working

[MImran2002]

Issue Description

Fixes issue #1791

• The new participant signature functionality is working for All Volunteers Training, but the signature pad is not currently displayed for participants in All CELTS Training.

Changes

• Fixed the Peewee training attendance logic so attended is consistently converted from a query into a single EventParticipant record before accessing .event.
• Prevented .get() from being called on an already-selected EventParticipant, which previously caused Peewee to run a new unfiltered query and return the wrong attendance record.
• Fixed the single-result case where attended remained a query and caused an error when attempting to access attended.event.

Testing

• Checkout the branch git checkout allVolTrainHotFix.
• Pull the branch git pull and ensure the branch is up to date.
• Reset the database with ./database/reset_database from-backup
• Run the application with flask run
• Go to Admin > Settings > Term Management and upload two documents each for different handbook for the current term
• Go to create an event for All Volunteer training and All CELTs Training. There make sure the term is current term and the event date is today with the time being right now so that the event is happening at the moment.
• As you would be default user Brian Ramsay, copy his B-number and individually add his B-number to both events in the Scanner Entry.
• Then go to his profile and click on Edit Personal Information to see the signature for the handbooks. Based on these participation combination you will see these:
  1). All Volunteer Training only- CELTS Student Handbook + Signature
  2). All Volunteer Training and All CELTS Training - CELTS Labor Handbook + Signature
  3). All CELTS Training - CELTS Labor Handbook + Signature
  4). None - CELTS Labor Handbook + Information to attend event

[bakobagassas]

@MImran2002 Some checks on GitHub are failing. Or maybe you already saw that?

[BrianRamsay]

We should make sure the hasGoneToTraining test breaks for the old code and passes for the new one.