Bluetooth: ascs: Fix ASE Codec Config PDU length validation

This moves ASE Control PDU length validation before request processing.
If the PDU length is not as expected, the operation shall be considered
as invalid. Thus shall be rejected.

ASCS_v1.0; 5 ASE Control operations
"A client-initiated ASE Control operation shall be defined as an invalid
 length operation if the total length of all parameters written by the
 client is not equal to the total length of all fixed parameters plus
 the length of any variable length parameters for that operation"

Fixes: #55747
Fixes: #55748
Signed-off-by: Mariusz Skamra <mariusz.skamra@codecoup.pl>