Remove unused calls to xdpw_request_create

[r3dey3]

The req object was not used and these calls were resulting with an error when attempting the pick-color from kdenlive on ubuntu 22.04 and 23.04

These objects were also not freed which is a memory leak.

[emersion]

Hm, I was under the impression that allocating D-Bus objects for these handles was important...

[r3dey3]

So I went and read through a bit of the docs (https://docs.flatpak.org/en/latest/portal-api-reference.html#gdbus-org.freedesktop.portal.Request) and other code - it looks like the code is supposed to respond with the Request object, then do the action (and if the Close method is called, cancel); then finally free up the request object.

I think the main issue why things aren't working is multi faceted -

1. The request object isn't actually sent in a reply - "the reply includes a handle (i.e. object path) for a Request object"
2. "handle... which will stay alive for the duration of the user interaction" - the request object needs to be released at the end of the user interaction
3. The code doesn't process dbus messages while waiting for user input - so the close method wouldn't be processed anyways.

Feel free to reject this pull request :-)

[emersion]

Superseded by #307