fix(frontend): fixes error screen alignment

[jenny-s51]

Description

Update navbar CSS to fix alignment for error screen, see attached images below. Test N/A, visual change only.

Before:

After:

How Has This Been Tested?

1. Start frontend and backend of Model Registry UI.

   Frontend:
   clients/ui/frontend && npm run start:dev

   Backend:
   clients/ui/bff && make run MOCK_K8S_CLIENT=true MOCK_MR_CLIENT=true

2.. Stop the backend to force error screen.

Merge criteria:

• All the commits have been signed-off (To pass the DCO check)

• The commits have meaningful messages; the author will squash them after approval or in case of manual merges will ask to merge with squash.
• Testing instructions have been added in the PR body (for PRs involving changes that are not immediately obvious).
• The developer has manually tested the changes and verified that the changes work.
• Code changes follow the kubeflow contribution guidelines.

If you have UI changes

• The developer has added tests or explained why testing cannot be added.
• Included any necessary screenshots or gifs if it was a UI change.
• Verify that UI/UX changes conform the UX guidelines for Kubeflow.

[google-oss-prow]

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