fix: Corrected bug in automatic refresh of tokens

[bflorian]

Fixed regression in automatic refreshing of tokens from asynchronous calls to the SmartThings platform (that is, calls not in response to lifecycle events).

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [x] I have read the CONTRIBUTING document
• [x] My code follows the code style of this project (hint: install an xo editor plugin)
• [ ] Any required documentation has been added
• [ ] I have added tests to cover my changes