Update dmi-stub details in test-deregistration script

dmi-plugin-stub was renamed to dmi-plugin-demo-and-csit-stub,
and port changed to 8092.

Issue-ID: CPS-1560
Signed-off-by: danielhanrahan <daniel.hanrahan@est.tech>
Change-Id: I3005087ace35aa131df720ed04c642d2d72f1255
1 file changed