Describe the bug

• Instructor makes a bulk upload gradeable

• First upload from a student OR from a instructor/TA uploading files for a student creates a submission for the student with a text file that does not include a "." Instead of naming the file "answers.txt" they just name it "answers".

• Then the instructor/TA bulk uploads pdf files for all students. Students who had earlier files named "answers.txt" are correctly identified and instructor/TA is allowed to merge that file with the second submissions upload.pdf file. But the student with just "answers" is not noticed, and there is no option to merge "answers" and "upload.pdf" into the new submission.

Expected behavior
It shouldn't matter what the file is named.