Fixed issue: --buildId will disnable --no-signing

Fixed issue:
1. `webworks build --release --buildId 1234 --no-signing`: `--no-signing` will be ignored when a `--buildId` is provided
2. `webworks build [--debug] --buildId 1234`: `--buildId` won't effect, which should be set in manifest of bar file.
If you leave the copyArgIfExists function you can remove this block of code entirely and simply move the `copyArgIfExists("buildId");` code to here.