[Build] Reenable components E2E tests on the CI

[javiercn]

These tests got disabled by f76be64 and further changes to the build infrastructure (likely due to 4fde84a) cause the tests to hang on the CI.

We should get to the bottom of this ASAP as it hurts our ability to deliver the product with confidence.

The change here is to replace

<SkipTests>true</SkipTests>

with

<SkipTests Condition="'$(SeleniumE2ETestsSupported)' != 'true'">true</SkipTests>                                                                                                                                                                               

on .\src\Components\test\E2ETest\Microsoft.AspNetCore.Components.E2ETests.csproj

and figure out why the component tests don't finish, as they finish on local builds.

[mkArtakMSFT]

@JunTaoLuo can you please handle this as soon as possible, as this has been a pain point for us.

[JunTaoLuo]

This will require expertise from the product area. Will you be able to help answer questions @javiercn when I investigate? I'm not sure if I can prioritize this above source build work in the short term though.

[dougbu]

Many thanks @rynowak