Fix Nightwatch overwriting test status set by user.

[garg3133]

Fixes: #3998

This PR does the following:

• If the status of a test is already found to be set in BrowserStack, it does not overwrite the status.
• Only request for builds currently running while trying to get the build id (otherwise if there are too many builds, the build used in the test run is never returned by BrowserStack, due to which the build id is set to undefined).

[github-actions]

Status

• ❌ No modified files found in the types directory.
  Please make sure to include types for any changes you have made. Thank you!.