Update git hash for duobaseio/forui

[Pante]

Updates the pinned commit for registry/forui.test from 5968a032 to 2b7b6876, the commit on duobaseio/forui main tagged 0.27.0.

• The main channel CI job for this commit passes.
• The customer test scripts (customer_test_setup.*, customer_test.*) are unchanged since the previously pinned commit.

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read the Flutter Style Guide recently, and have followed its advice.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[Pante]

For transparency, CLA bot fired because Claude was a co-author.