Select all only reaches the first 500 items

## Describe the Bug
I just imported from LastPass and wanted to check if the number of imported entries match what I see in that. I have 583 entries, but it stops selecting after 500, even if I scroll all the way down (some lazyload maybe).

1. Go to my vault,
2. Cogwheel menu
3. Select all.
4. I choose the move option just because it tells me the number, and it shows just 500.

## Expected Result

I'd like to really select all, for counting or actual moving.

## Actual Result

Selection has an upper limit.

## Environment

- Operating system: Windows 10
- Browser: Vivaldi 3.6
- Build Version (Bottom of the page): Version 2.18.1

Reproduce the issue in the vault by using the Cogwheel menu and Select all with more than 500 entries, then inspect the selection behavior around lazy-loaded items. Done means all imported entries, including the 583-item example, are selected and the move flow reports the full count.

Written by the indexing model from the issue text.