Query pagination and download all does not work for big objects

[paustint]

Describe the bug and steps to reproduce
User reported with ReportEvent but was able to reproduce something similar using a custom big object.

There are some cases where totalSize is not correct and we should protect against such cases.

Areas to consider (may not be exhaustive)

1. showing x of x on query results
2. load more
3. download modal does not give option to "download remaining X)

Check anywhere where we are using totalSize from query results