fix validippassword

abstracted ap password validation
passing a invalid password should be fatal , not fallback to null, but
could be an optional define

WiFiManager.cpp

@@ -176,7 +176,7 @@ boolean  WiFiManager::startConfigPortal(char const *apName, char const *apPasswo
 
   _apName     = apName;
   _apPassword = apPassword;
-  if(!validApPassword) return;
+  if(!validApPassword()) return false;
 
   // do AP callback if set
   if ( _apcallback != NULL) {
@@ -833,7 +833,7 @@ String WiFiManager::toStringIp(IPAddress ip) {
   return res;
 }
 
-bool WiFiManager::validApPassword(){
+boolean WiFiManager::validApPassword(){
   // check that ap password is valid, return false
   if (_apPassword != NULL) {
     if (strlen(_apPassword) < 8 || strlen(_apPassword) > 63) {

WiFiManager.h

@@ -170,7 +170,6 @@ class WiFiManager
     void          handle204();
     boolean       captivePortal();
     boolean       configPortalHasTimeout();
-    boolean       validApPassword();
     
     // DNS server
     const byte    DNS_PORT = 53;
@@ -179,6 +178,7 @@ class WiFiManager
     int           getRSSIasQuality(int RSSI);
     boolean       isIp(String str);
     String        toStringIp(IPAddress ip);
+    boolean       validApPassword();
 
     boolean       connect;
     boolean       _debug = true;