fix: handle undefined pathname in URL builder (#2021)

* fix: handle undefined pathname in URL builder

Return early when pathname is undefined to avoid inserting an extra ':'
and strip a leading '/' from newDocId before concatenation

* Update src/utils/Url.js

Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>

* Update Url.js

* fix(Url): root/docId separator in Url util

Move pathname handling into the correct branch and ensure a ':' is
inserted between root and newDocId when appropriate

* feat: URL tests and include them in test runner

* chore: reorder imports in url.test.js

* chore: Bump @biomejs/biome to ^2.4.11

* Update biome.json

* fix

* fix

* chore: update biome

* fix: tests

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Co-authored-by: greptile-apps[bot] <165735046+greptile-apps[bot]@users.noreply.github.com>
Co-authored-by: Raunak Raj <71929976+bajrangCoder@users.noreply.github.com>