Bump Selenium.Axe and Selenium.WebDriver

Bumps [Selenium.Axe](https://github.com/TroyWalshProf/axe-selenium-csharp) and [Selenium.WebDriver](https://github.com/SeleniumHQ/selenium). These dependencies needed to be updated together.

Updates `Selenium.Axe` from 4.0.14 to 4.0.21
- [Release notes](https://github.com/TroyWalshProf/axe-selenium-csharp/releases)
- [Commits](TroyWalshProf/SeleniumAxeDotnet@v4.0.14...v4.0.21)

Updates `Selenium.WebDriver` from 4.16.2 to 4.19.0
- [Release notes](https://github.com/SeleniumHQ/selenium/releases)
- [Commits](https://github.com/SeleniumHQ/selenium/commits/selenium-4.19.0)

---
updated-dependencies:
- dependency-name: Selenium.Axe
  dependency-type: direct:production
  update-type: version-update:semver-patch
- dependency-name: Selenium.WebDriver
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

DigitalLearningSolutions.Web.AutomatedUiTests/DigitalLearningSolutions.Web.AutomatedUiTests.csproj

@@ -10,7 +10,7 @@
     <PackageReference Include="FluentAssertions" Version="5.10.3" />
     <PackageReference Include="Microsoft.AspNetCore.Mvc.Testing" Version="6.0.25" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.8.0" />
-    <PackageReference Include="Selenium.Axe" Version="4.0.14" />
+    <PackageReference Include="Selenium.Axe" Version="4.0.21" />
     <PackageReference Include="Selenium.Support" Version="4.27.0" />
     <PackageReference Include="Selenium.WebDriver" Version="4.27.0" />
     <PackageReference Include="Selenium.WebDriver.ChromeDriver" Version="122.0.6261.11100" />