[#389] Removed aria-label from button with 'is_new_window'.

[alan-cole]

https://github.com/civictheme/uikit/issues/389

Checklist before requesting a review

• [x] I have formatted the subject to include the issue number as [#123] Verb in past tense with a period at the end.
• [x] I have provided information in the Changed section about WHY something was done if this was a bespoke implementation.
• [x] I have performed a self-review of my code.
• [x] I have commented on my code, particularly in hard-to-understand areas.
• [ ] I have added tests that prove my fix is effective or that my feature works.
• [x] I have run new and existing relevant tests locally with my changes, and they have passed.
• [x] I have provided screenshots, where applicable.

Changed

1. The aria-label in this case would override whatever text was present within the button, meaning buttons lose context if used with a screen reader.

Screenshots

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 13.87%. Comparing base (343d1ff) to head (15b2d31). Report is 6 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #390 +/- ## ======================================= Coverage 13.87% 13.87% ======================================= Files 27 27 Lines 1290 1290 Branches 307 307 ======================================= Hits 179 179 Misses 894 894 Partials 217 217 ```

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

[github-actions[bot]]

🚀 Deployed on https://66f39424ac1c22a7f3222715--civictheme-uikit.netlify.app