Checkboxes on purchase order screen have no accessible name

[Jane Sandberg]

Steps to recreate:

1) Open a purchase order (in the new angular version)
2) Note that each line item has a checkbox to the left of the title.
3) Inspect the accessibility properties of the checkbox using your browser.
4) Note that there is no accessible name.

The impact: if somebody is using a screenreader, they would have to use context to understand what the checkbox is for, and which line item it even pertains to.

One possible implementation:
1) Give each line item ID display (#1, #2, etc.) a unique ID
2) Add an aria-labelledby attribute to the checkbox to point to that id

[Stephanie Leary (stephanieleary)]

Branch: https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/sleary/lp2009092-acq-lineitem-checkbox-labels

I've found numerous other accessibility issues with this screen, but I will file those separately.

[Terran McCanna (tmccanna)]

I confirm that this adds the label to the checkboxes! Sign off at:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/mccanna/lp2009092-acq-lineitem-checkbox-signoff

[Jane Sandberg (sandbergja)]

Thanks, Stephanie and Terran! Pushed to rel_3_10 and above.