This should prevent a crash we've seen on Crashlytics.

Why is this the best possible solution? Were any other approaches considered?

The original code would end up calling handleScannerResult twice: once when the action is clicked and once when the snackbar is dismissed. This didn't cause any obvious problems, but ran the risk of a requireActivity call after the first call's finish had already happened. I've now made it so that handleScannerResult is only called once, and hopefully made our API around snackbars clearer to avoid a similar mistake in future.

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

It's probably impossible to reliably reproduce the crash. So just testing normal barcode scanning is enough here.

Before submitting this PR, please make sure you have:

• added or modified tests for any new or changed behavior
• run ./gradlew connectedAndroidTest (or ./gradlew testLab) and confirmed all checks still pass
• added a comment above any new strings describing it for translators
• added any new strings with date formatting to DateFormatsTest
• verified that any code or assets from external sources are properly credited in comments and/or in the about file.
• verified that any new UI elements use theme colors. UI Components Style guidelines