selftests/hid: tablets: convert the primary button tests

selftests/hid: tablets: convert the primary button tests

We get more descriptive in what we are doing, and also get more
information of what is actually being tested. Instead of having a non
exhaustive button changes that are semi-randomly done, we can describe
all the states we want to test.

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Jiri Kosina <jkosina@suse.com>
Link: https://lore.kernel.org/r/20231206-wip-selftests-v2-11-c0350c2f5986@kernel.org
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>