Update gov-uk-dashboards requirement from ~=28.2.0 to ~=28.4.0

Updates the requirements on [gov-uk-dashboards](https://github.com/communitiesuk/pkg_gov_uk_dashboards) to permit the latest version.
- [Release notes](https://github.com/communitiesuk/pkg_gov_uk_dashboards/releases)
- [Commits](communitiesuk/pkg_gov_uk_dashboards@v28.2.0...v28.4.0)

---
updated-dependencies:
- dependency-name: gov-uk-dashboards
  dependency-version: 28.4.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

requirements.txt

@@ -9,7 +9,7 @@ black~=26.3.0
 black[jupyter]~=26.3.0
 pyodbc~=5.3.0
 numpy~=2.4.3
-gov-uk-dashboards~=28.2.0
+gov-uk-dashboards~=28.4.0
 uk-gov-dash-components~=2.1.0
 dash[testing]~=3.4.0
 chromedriver-autoinstaller~=0.6.4