When the PSA RNG uses AES through a PSA driver, it consumes one volatile key
identifier. When MBEDTLS_PSA_KEY_SLOT_DYNAMIC is enabled, that identifier
happens to coincide with the key ID value that the test case assumes not to
exist. Use a different value that avoids this coincidence.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>