wifi_prov_mgr: keep SoftAP transport as default only for ESP32S2

This allows to have default transport as BLE for all chips except
ESP32S2.

examples/provisioning/wifi_prov_mgr/main/Kconfig.projbuild

@@ -2,6 +2,7 @@ menu "Example Configuration"
 
     choice EXAMPLE_PROV_TRANSPORT
         bool "Provisioning Transport"
+        default EXAMPLE_PROV_TRANSPORT_SOFTAP if IDF_TARGET_ESP32S2
         default EXAMPLE_PROV_TRANSPORT_BLE
         help
             Wi-Fi provisioning component offers both, SoftAP and BLE transports. Choose any one.
@@ -9,7 +10,6 @@ menu "Example Configuration"
         config EXAMPLE_PROV_TRANSPORT_BLE
             bool "BLE"
             select BT_ENABLED
-            depends on IDF_TARGET_ESP32
         config EXAMPLE_PROV_TRANSPORT_SOFTAP
             bool "Soft AP"
     endchoice