Update Probe Response template on channel switch

Update Probe Response template on channel switch

When AP is beaconing only on the 6 GHz band and unsol_bcast_presp
interval is set, AP sends unsolicited broadcast Probe Response frames
for in-band discovery. hostapd sent the Probe Response template for this
frame only when setting a new Beacon frame template.

Extend this to update the Probe Response template during channel switch.

Signed-off-by: Rathees Kumar R Chinannan <quic_rrchinan@quicinc.com>