Remove overzealous encoding of error parameters

Output encoding happens in the view. This prevents the encoded stuff
from ending up in other places, including log files. Also fixes
tests that were broken because of this.

src/SimpleSAML/Error/AuthSource.php

@@ -43,8 +43,8 @@ class AuthSource extends Error
         parent::__construct(
             [
                 'AUTHSOURCEERROR',
-                '%AUTHSOURCE%' => htmlspecialchars(var_export($this->authsource, true)),
-                '%REASON%' => htmlspecialchars(var_export($this->reason, true))
+                '%AUTHSOURCE%' => $this->authsource,
+                '%REASON%' => $this->reason
             ],
             $cause
         );

src/SimpleSAML/Error/MetadataNotFound.php

@@ -24,7 +24,7 @@ class MetadataNotFound extends Error
         $this->includeTemplate = 'core:no_metadata.twig';
         parent::__construct([
                 'METADATANOTFOUND',
-                '%ENTITYID%' => htmlspecialchars(var_export($entityId, true))
+                '%ENTITYID%' => $entityId
         ]);
     }
 }

tests/modules/saml/src/Controller/ServiceProviderTest.php

@@ -299,8 +299,7 @@ class ServiceProviderTest extends TestCase
         $c = new Controller\ServiceProvider($this->config, $this->session);
 
         $this->expectException(Error\MetadataNotFound::class);
-// Breaks PHP 8.1 tests
-//        $this->expectExceptionMessage("METADATANOTFOUND('%ENTITYID%' => '\'https://engine.test.surfconext.nl/authentication/idp/metadata\'')");
+        $this->expectExceptionMessage("METADATANOTFOUND('%ENTITYID%' => 'https://engine.test.surfconext.nl/authentication/idp/metadata')");
 
         $c->assertionConsumerService('phpunit');
     }
@@ -388,8 +387,7 @@ XML;
         $c = new Controller\ServiceProvider($this->config, $this->session);
 
         $this->expectException(Error\MetadataNotFound::class);
-// Breaks PHP 8.1 tests
-//        $this->expectExceptionMessage("METADATANOTFOUND('%ENTITYID%' => '\'https://engine.test.surfconext.nl/authentication/idp/metadata\'')");
+        $this->expectExceptionMessage("METADATANOTFOUND('%ENTITYID%' => 'TheIssuer')");
 
         $c->singleLogoutService('phpunit');
     }