test(react): Add gql tests for react router

[github-actions]

Note

The pull request "test(react): Add gql tests for react router" was created by @chargome but did not reference an issue. Therefore this issue was created for better visibility in external tools like Linear.

• Adds E2E tests verifying that GraphQL fetch spans are attributed to the correct navigation transaction in React Router 7 lazy routes
• Test 1: Navigate from index to lazy GQL page → asserts UserAQuery span is in the navigation transaction (not the pageload)
• Test 2: Navigate between two lazy GQL pages → asserts UserAQuery only in first nav, UserBQuery only in second nav, no cross-leaking

[linear-code]

JS-1953

[github-actions]

A PR closing this issue has just been released 🚀

This issue was referenced by PR #19844, which was included in the 10.45.0 release.