Wifi-HAL: Convert whitelist SSIDs as byte arrays of 32 length

StaRoamingConfig.ssidWhitelist is defined as vector of 32 length byte
array in HAL definition. Due to this SSIDs with lesser lengths are
getting rejected by HIDL with invalid argument exception.

This commit is to convert all whitelist SSIDs to fixed length 32
bytes by padding null/0's to pass the HAL validation and Vendor
HAL's can detect the actual length by checking first occurrence of
null/0 in byte array.

BYPASS_INCLUSIVE_LANGUAGE_REASON=existing class properties

Bug: 172776379
Test: atest WifiVendorHalTest
Change-Id: I856b15a52c10940fe64414976ec9b027d699e428
2 files changed