Revert "glupload: Fix caps query with no filter"

Revert "glupload: Fix caps query with no filter"

This reverts commit 6f9ae5d7580763b5d18badb76f2166ff0012886a.

The _transform_caps() function can't tell the difference
between the caller wanting to know the output caps
for the current method, or all possible output caps. If
it includes caps for all possible methods, glupload can
end up negotiating and sending the wrong output caps
downstream.

Partially reverts !2687
Fixes #1310

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2699>