Remove useless ignore rules

The referenced issue is fixed, but the fix is not released yet. However,
since the "tests" directory is not currently analyzed, the ignore rule
is useless.
Also the rule about ignoing the vendor directory is useless.

psalm.xml

@@ -10,10 +10,7 @@
     <projectFiles>
         <directory name="lib/Doctrine/Common" />
         <ignoreFiles>
-            <!-- Remove ProxyGeneratorTest once Psalm supports native intersection https://github.com/vimeo/psalm/issues/6413 -->
             <file name="lib/Doctrine/Common/Proxy/ProxyGenerator.php" />
-            <file name="tests/Doctrine/Tests/Common/Proxy/ProxyGeneratorTest.php" />
-            <directory name="vendor" />
         </ignoreFiles>
     </projectFiles>
 </psalm>