d/wmr: fix squeeze trigger in SteamVR
While in the Monado debug GUI the squeeze trigger is detected fine and it is also listed in the SteamVR "Test Controller" page, pushing the squeeze trigger would not be detected in SteamVR.
Fixing this by not just populating the xrt_inputs squeeze click but also the squeeze value.
Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue>