fix(android): wait for emulator framework boot

[huytdps13400]

Summary

• keep polling after adb devices reports the launched emulator until that serial returns sys.boot_completed=1
• use the connected serial selected by the requested emulator port for the framework readiness check
• increase the cold-boot timeout from 30 seconds to 120 seconds so slower machines and CI can finish booting

Fixes #2824

Test Plan

• RED: the new fake-timer tests resolved as soon as adbd appeared and timed out after only 30 seconds before the implementation change
• yarn test packages/cli-platform-android/src/commands/runAndroid/__tests__/tryLaunchEmulator.test.ts --runInBand (2 passed)
• yarn test packages/cli-platform-android --runInBand (5 suites, 19 passed)
• yarn test:ci:unit (56 suites, 315 passed, 1 pre-existing todo)
• yarn lint (0 errors; 2 pre-existing warnings outside this diff)
• yarn build
• git diff --check

All commands above ran with Node 22.22.2, matching the repository CI matrix.

Checklist

• Documentation is up to date; this changes the internal readiness signal without changing CLI options.
• Follows commit message convention described in CONTRIBUTING.md.
• For functional changes, my test plan has linked these CLI changes into a local react-native checkout. The cold-boot timing and timeout behavior are covered deterministically with mocked ADB responses and fake timers instead.

[huytdps13400]

Thanks for the approval. I checked the failed Node 20 Ubuntu E2E job. It is unrelated to the Android emulator boot change:

• the only asserted failure is __e2e__/config.test.ts because the generated config now contains the base branch's spm [action] command while the snapshot does not
• the log also contains existing E2E fixture setup failures from yarn link .../__e2e__ --all and ESM config fixtures using require
• lint and both Node 20/22 unit suites pass

The other E2E matrix jobs were cancelled after this fail-fast result. There is no Android/emulator failure in the run and no PR code change is indicated; a rerun after the base E2E snapshot/fixture is corrected should be sufficient.