Improve emulator lifecycle reliability (boot/cpu/animation exception handling)

[mattleibow]

Ref: PR #63

The following improvements were identified during review of PR #63 to improve reliability and handle transient ADB failures:

1. WaitForBootComplete: The adb.Shell calls inside the polling loop (lines ~355) can throw SdkToolFailedExitException if adb exits non-zero. These should be wrapped in a try-catch block to allow retrying, similar to FindRunningEmulatorSerialByAvdName.
2. WaitForCpuLoadBelow: The adb.Shell call (line ~401) should also be wrapped in try-catch to handle transient failures.
3. DisableAnimations: The adb.Shell calls (line ~429) should be best-effort and wrapped in try-catch.
4. Test Coverage: Add tests for DisableAnimations and the new launcher waiting logic in WaitForBootComplete.
5. Cleanup: Remove unused using System.Data; in Emulator.cs.