Regression: if no network adapters are available, rapps will display wrong error message

Tested reactos-bootcd-0.4.15-dev-1356-g44c6df4-x86-gcc-lin-dbg in virtualbox 6.1.16 r140961.

Steps to reproduce:

1. Disable all network adapters.
2. Run reactos and try to update rapps database. Wait long enough.

Expected: rapps displays a message with text "Unable to download the package! Check Internet Connection!"

Got: a message with text "Posting this operation to a worker thread for further processing is not safe at this time because it could lead to a system deadlock."

Tested these builds:

reactos-bootcd-0.4.15-dev-1356-g44c6df4-x86-gcc-lin-dbg

reactos-bootcd-0.4.15-dev-678-gfa8ce68-x86-gcc-lin-dbg

reactos-bootcd-0.4.15-dev-339-g7c9a8c0-x86-gcc-lin-dbg

reactos-bootcd-0.4.15-dev-170-g1f3cb13-x86-gcc-lin-dbg

reactos-bootcd-0.4.15-dev-155-gcf9ba2b-x86-gcc-lin-dbg

There weren't any gcc builds in between. I was using msvc builds to find a candidate commit.

reactos-bootcd-0.4.15-dev-148-gbfd02fa-x86-msvc-win-dbg

reactos-bootcd-0.4.15-dev-146-gfb1582d-x86-msvc-win-dbg

reactos-bootcd-0.4.15-dev-145-g8c4b0c9-x86-msvc-win-dbg

reactos-bootcd-0.4.15-dev-142-gc276681-x86-gcc-lin-dbg

reactos-bootcd-0.4.15-dev-141-gb3947d5-x86-gcc-lin-dbg

reactos-bootcd-0.4.15-dev-127-gd62b1a9-x86-gcc-lin-dbg

reactos-bootcd-0.4.15-dev-85-g8c5c47e-x86-gcc-lin-dbg

reactos-bootcd-0.4.15-dev-1-gd328584-x86-gcc-lin-dbg