Misleading "Some files could not be synced!"

[i2h3]

• Launching the client with a single account configured with file provider only results in the "Some files could not be synced!" message in the tray window popover despite everything being fine.
• The problem is the lack of status information for which the app defaults to this message.
• Relevant code: syncstatussummary.cpp:251 where case SyncResult::Undefined: is handled.
• Force the file provider extension to report its (hopefully happy) state on launch to avoid the default undefined fallback with the misleading message.