selftests/hid: add another test for injecting an event from an event hook

Similar to test_multiply_events_wq: we receive one event and inject a
new one. But given that this time we are already in the event hook, we
can use hid_bpf_try_input_report() directly as this function will not
sleep.

Note that the injected event gets processed before the original one this
way.

Link: https://patch.msgid.link/20240626-hid_hw_req_bpf-v2-12-cfd60fb6c79f@kernel.org


Acked-by: Jiri Kosina <jkosina@suse.com>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>