wifi: Add new HAL API: getBridgedInstances

Also fix the instances doesn't update after removing the instance

Cherry-pick from ag/13382534 which finished the review in master branch

Bug: 173999527
Test: atest -c VtsHalWifiApV1_5TargetTest

Change-Id: I439922d38c35b5367823f95f5f7d0e4c6ed05f57
diff --git a/wifi/1.5/default/wifi_chip.cpp b/wifi/1.5/default/wifi_chip.cpp
index fbb4a52..50836cc 100644
--- a/wifi/1.5/default/wifi_chip.cpp
+++ b/wifi/1.5/default/wifi_chip.cpp
@@ -1067,6 +1067,7 @@
         }
     }
     br_ifaces_ap_instances_.erase(ifInstanceName);
+    iface->removeInstance(ifInstanceName);
     return createWifiStatus(WifiStatusCode::SUCCESS);
 }