Increase 2FA key size

When scanning the 2FA codes with FreeOTP it reports that the tokens contain insecure cryptographic parameters. The key is too short. Google authenicator standard is 32 characters.

Author: tvlooy

plugins/TwoFactorAuth/Dao/TwoFaSecretRandomGenerator.php

@@ -16,6 +16,6 @@ class TwoFaSecretRandomGenerator
     public function generateSecret()
     {
         $authenticator = new \TwoFactorAuthenticator();
-        return $authenticator->createSecret(16);
+        return $authenticator->createSecret(32);
     }
 }

plugins/TwoFactorAuth/tests/Integration/Dao/TwoFaSecretRandomGeneratorTest.php

@@ -33,7 +33,7 @@ public function setUp(): void
 
     public function testGeneratorCodeLength()
     {
-        $this->assertSame(16, mb_strlen($this->generator->generateSecret()));
+        $this->assertSame(32, mb_strlen($this->generator->generateSecret()));
     }
 
     public function testGeneratorCodeAlwaysDifferent()

plugins/TwoFactorAuth/tests/Integration/TwoFactorAuthenticationTest.php

@@ -56,7 +56,7 @@ public function setUp(): void
 
     public function testGenerateSecret()
     {
-        $this->assertSame(16, mb_strlen($this->twoFa->generateSecret()));
+        $this->assertSame(32, mb_strlen($this->twoFa->generateSecret()));
     }
 
     public function testIsUserRequiredToHaveTwoFactorEnabledNotByDefault()