samples/subsys/mgmt/osdp: Fix build issues

The samples/subsys/mgmt/osdp utilize GPIO so having it set in the
prj.conf is needed since not all platforms enable GPIO by default.

To address the 'No SOURCES given to Zephyr library: drivers__gpio'
add a 'depends on gpio' to the sample.yaml to only build this on
platforms that have GPIO driver support.

Fixes #39180

Signed-off-by: Kumar Gala <kumar.gala@linaro.org>