Improve Error Handling for Mass Update Check

[ImranR98]

On the Apps list page, checking for updates using pull to refresh can sometimes result in an error that gets displayed in a snackbar. But the message doesn't specify which App caused the error. This is probably also true for background update notifications.

Also, one error caused by some App results in all other remaining Apps not being checked, which is not ideal. Instead, all Apps should be checked and any errors should be collected in an array and displayed at the end (summarized in 1-2 lines due to space constraints).

[ImranR98]

Done: https://github.com/ImranR98/Obtainium/releases/tag/v0.5.9-beta