Workshop: Support new submission type setting

Moodle 3.6

1. Create a workshop and repeat the next steps with the different combinations of "Submission types":

   Online text	File attachment
   Required	Disabled
   Disabled	Required
   Required	Available
   Available	Required
   Available	Available
   Required	Required

1. Access the workshop in the app as a student.
2. Create a new submission, fil the title and try to send it with on of the required fields missing. Check that a modal is shown warning about the missing field.
3. Fill the text and/or add a file and submit. Check the submission has been created in web.
4. Edit the submission and save it. Check that the submission has been updated in web.
5. Delete the submission on web and create a new submission on the app in offline.
6. With the app online, pull to refresh to sync the offline submission. Check that the submission has been created on web.

Moodle 3.4 / 3.5

1. Create a workshop and set the number of allowed attachments to 0.
2. Access the workshop in the app as a student and try send the submission with no text. Check that a modal is displayed warning about the missing text.
3. Fill the text and send the submission. Check that the submission is created on web.
4. Delete the submission and change the number of allowed attachments to >= 1.
5. Access the workshop in the app as a student and try send the submission with no text and no files. Check that a modal is displayed warning about the missing fields.
6. Attach a file and send the submission. Check that the submission is created on web.