Wifi: Remove @SystemApi annotation from SOFTAP_FEATURE_WPA3_OWE

SOFTAP_FEATURE_WPA3_OWE is a vendor specific public API and must
not be a systemApi. The commit removes @systemApi tag for above variable
to avoid CTS failures.

Change-Id: I9fa0c2f279fc6ada5dfeef6f4be43023ffe35378
CRs-Fixed: 2729338
3 files changed