Intermittent loading issue with settings

[jcope]

• Remove the .catch(() => {}) from load_from_browser. That could be silently discarding an error message about failure to open or read from the database. AND/OR
• Check or assert that event.target.result isn’t undefined on line 710.
• See if there’s a Puppeteer option to delete any persistent storage on start-up. Could headless Chrome be persisting the indexedDB stores between executions?

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References controlpanel.js:570 and checking for settings are undefined. Occasionally, but not all the time, loading settings would return null object, causing Dasher to crash. Issue was discovered with PR23, and implementation of automated testing.