samples: tests: Create dedicated test section for rd_rw612_bga

Monolithic build is enabled by default and it
requires the presence of the binary blobs.
CI will fail since it doesn't fetch them
to the environment. To avoid this
monolithic for BT app is disabled.

Signed-off-by: Yassine El Aissaoui <yassine.elaissaoui@nxp.com>