Fix #1008: Sourced conflicting holidays being imported by default

[tupaschoal]

Related issue

Closes #1008

Context / Background

When sourcing holidays, the ones matching existing waivers were tagged as conflicts, but still picked to be added nonetheless

What change is being introduced by this PR?

Now when a conflict is detected, the checkbox will be unchecked by default and also disabled. Turns out that all we needed was to either set the checked attribute or not, but we were instead doing checked='' or checked=checked and it always thought it was checked.

• Do we really want to disable it? If the user wants to import conflicting waivers, then we might as well allow it.

How will this be tested?

Test manually, but there are automatic tests for it that I hope still work

[araujoarthur0]

Thanks @tupaschoal.
I think we can go for the unchecked by default, but not disable the checkboxes.
If any conflict is checked, then we display the alert saying "conflicts will be overwritten".
And then we actually overwrite them (which seems to already be happening, although currently we display two at the table until the window is refreshed).

[codecov]

Codecov Report

Merging #1011 (9f9d886) into main (237e6b3) will not change coverage.
Report is 1 commits behind head on main.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1011   +/-   ##
=======================================
  Coverage   75.04%   75.04%           
=======================================
  Files          26       26           
  Lines        2188     2188           
  Branches      345      345           
=======================================
  Hits         1642     1642           
  Misses        546      546           

Files	Coverage Δ
src/workday-waiver.js	76.98% <100.00%> (ø)

[tupaschoal]

@araujoarthur0 I think we should move forward without the pop-up, and add that as another task, since it involves more work and writing new tests (for covering the pop-up and etc)

[araujoarthur0]

\changelog-update