chore(init): remove error when Git initialisation failed

[szymonrybczak]

Summary:

It may be confusing when we throw an error while initialising Git repo, let's just don't give any information since isn't not-blocking thing. Reference: #2212

Test Plan:

1. Clone the repository and do all the required steps from the Contributing guide
2. Put throw new Error('Git commit failed'); on 57th line in createGitRepository.ts file.
3. Run this command:

node /path/to/react-native-cli/packages/cli/build/bin.js init

Git repo init loader shouldn't be presented.

Checklist

• Documentation is up to date to reflect these changes.
• Follows commit message convention described in CONTRIBUTING.md