Teammates: Instructor: enroll students: blank lines processed by back-end during enrollment

[tanhengyeow]

Environment:
master branch

Steps to reproduce

1. Copy rows of student entries from external sources e.g. Microsoft Excel. Sample data shown below:

1. Paste the content into the New Students spreadsheet using Ctrl + V or Cmd + V:

1. Click the Enroll students button.

Expected behaviour

1. Success enrollment. Example shown below:

Actual behaviour

1. Blank lines processed by back-end during enrollment:

Additional info

1. This is due to potential line feeds/carriage returns during the process of copying data from external sources.
2. This causes the backend method getRequestParamValue to read in the line feeds/carriage returns, resulting in student entries to be read separated rows. Example shown below:

[damithc]

On a somewhat related note, aren't we supposed to ignore blank lines anyway?

[tanhengyeow]

@damithc

Yes, the front-end now currently does this:

1. Filter empty rows first
2. Send the non-empty lines to the backend

However, in this case, there were unexpected line feeds/carriage returns due to copying from other sources, resulting in a new "empty line" to be formed. The unexpected empty lines weren't filtered at this point.

This resulted in the back-end returning the error messages shown in the description after checking the relevant enroll line. The hotfix I'm submitting now takes care of all the line feeds and carriage returns.

[xpdavid]

@damithc Done. Released as V6.10.1.

[damithc]

I've deployed v6.10.1

[damithc]

Thanks for the quick fix and quick release @tanhengyeow @xpdavid