shields: nrf7002eb: Fix 54H app core boot

With recent SDSC bundles, 54H fails the app core boot in case of a
unsupported GPIO in the UICR.

As Wi-Fi SR co-existence on nRF54H20DK is not yet supported, remove this
GPIO for 54H. This will be fixed properly once co-existence is
revisited.

Signed-off-by: Chaitanya Tata <Chaitanya.Tata@nordicsemi.no>