Display add button in header for TWL when no items

[kintsoogi]

Describe what your pull request addresses

• [ ] Display add button in header for TWL when no items #585
• [ ] Do not display delete button if no items in tsv resource card

Test Instructions

• [ ] Either navigate to a reference where there are no TWL items or delete all current TWL items (make sure you are on QA)
  • [ ] Verify that add button shows in header when there are no TWL items
  • [ ] Add tsv item to TWL and verify that TWL shows
• [ ] Do the same for either TN or TQ. Verify that delete button in header does not show when there are no items

[codecov[bot]]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (f39feac) 50.59% compared to head (acd6bcf) 51.72%.

Files	Patch %	Lines
src/components/ResourceCard.js	71.42%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #597 +/- ## =========================================== + Coverage 50.59% 51.72% +1.12% =========================================== Files 43 43 Lines 1338 1336 -2 =========================================== + Hits 677 691 +14 + Misses 661 645 -16 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.