tests(phpstan): Remove PHPStan config exceptions that have been fixed in upstream PHPCS

coder_sniffer/Drupal/Sniffs/Files/LineLengthSniff.php

@@ -49,7 +49,7 @@ class LineLengthSniff extends GenericLineLengthSniff
      * @param array<int, array>           $tokens    The token stack.
      * @param int                         $stackPtr  The first token on the next line.
      *
-     * @return false|null
+     * @return void
      */
     protected function checkLineLength($phpcsFile, $tokens, $stackPtr)
     {

composer.json

@@ -16,7 +16,7 @@
     "require": {
         "php": ">=7.0.8",
         "ext-mbstring": "*",
-        "squizlabs/php_codesniffer": "^3.5.5",
+        "squizlabs/php_codesniffer": "^3.5.6",
         "symfony/yaml": ">=2.0.5",
         "sirbrillig/phpcs-variable-analysis": "^2.8"
     },

phpstan.neon

@@ -73,12 +73,3 @@ parameters:
             message: "#^Strict comparison using \\=\\=\\= between true and false will always evaluate to false\\.$#"
             count: 1
             path: coder_sniffer/Drupal/Sniffs/Commenting/DocCommentSniff.php
-        # Wrong return type in PHPCS https://github.com/squizlabs/PHP_CodeSniffer/pull/2816
-        -
-            message: "#^Method Drupal\\\\Sniffs\\\\Files\\\\LineLengthSniff\\:\\:checkLineLength\\(\\) should return false\\|null but empty return statement found\\.$#"
-            count: 4
-            path: coder_sniffer/Drupal/Sniffs/Files/LineLengthSniff.php
-        -
-            message: "#^Method Drupal\\\\Sniffs\\\\Files\\\\LineLengthSniff\\:\\:checkLineLength\\(\\) should return false\\|null but return statement is missing\\.$#"
-            count: 1
-            path: coder_sniffer/Drupal/Sniffs/Files/LineLengthSniff.php