fix: refactor nav bar to be more testable, add unit tests

[everettbu]

Mirror of supabase/supabase#43867
Original author: awaseem

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I have read the CONTRIBUTING.md file.

YES

What kind of change does this PR introduce?

• refactor navigation utils to pass in is_platform
• write unit tests for configuration returns
• default is always passed from constant IS_PLATFORM

[github-actions]

🎭 Playwright Test Results

 158 passed
 5 skipped

Details

 163 tests across 20 suites
 2 minutes, 54 seconds
 a7c7b33

Skipped tests

Features › assistant.spec.ts › AI Assistant › Can send a message to the assistant and receive a response
Features › sql-editor.spec.ts › SQL Editor › snippet favourite works as expected
Features › sql-editor.spec.ts › SQL Editor › share with team works as expected
Features › sql-editor.spec.ts › SQL Editor › folders works as expected
Features › sql-editor.spec.ts › SQL Editor › other SQL snippets actions work as expected