A low-frequency error that showed up in telemetry for new bookmark
sync is "Storage operation failed with NS_ERROR_CANNOT_CONVERT_DATA",
which occurs when we try to convert a variant to the wrong type. It
would be helpful to include the type and column names for this case;
for example, "Can't get i32 for column lastModified". Neither the type
nor column name are PII; we want them to show up in telemetry.
Differential Revision: https://phabricator.services.mozilla.com/D46433
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extra : moz-landing-system : lando
