Tizen.Network.WiFi: Fix to use Marshal.FreeHGlobal instead of Interop.Libc.Free (#7282)

The allocation in the native function call is called from libgwpasan and
free is called from glibc, and it causes crash on ASAN environment.

To resolve this issue, Marshal.FreeHGlobal() is used instead of
Interop.Libc.Free().

Signed-off-by: MyoungJune Park <renov.park@samsung.com>

Author: MyoungJunePark

src/Tizen.Network.WiFi/Tizen.Network.WiFi/WiFiManagerImpl.cs

@@ -720,7 +720,7 @@ internal string TDLSConnectedPeer
                 else
                 {
                     _tdlsMacAddress = Marshal.PtrToStringAnsi(strPtr);
-                    Interop.Libc.Free(strPtr);
+                    Marshal.FreeHGlobal(strPtr);
                 }
 
                 Log.Info(Globals.LogTag, "Tdls Mac address: " + _tdlsMacAddress);