Cleanup After Phpstan Upgrade (#2800)

After Phpstan 1.6.3 upgrade, clean up some new problems that will show up if it runs under Php 8+.

phpstan-conditional.php

@@ -46,6 +46,13 @@ if (PHP_VERSION_ID < 80000) {
         'path' => __DIR__ . '/src/PhpSpreadsheet/Shared/StringHelper.php',
         'count' => 1,
     ];
+} else {
+    // Flagged in Php8+ - unsure how to correct code
+    $config['parameters']['ignoreErrors'][] = [
+        'message' => '#^Binary operation "/" between float and array[|]float[|]int[|]string results in an error.#',
+        'path' => __DIR__ . '/src/PhpSpreadsheet/Calculation/MathTrig/Combinations.php',
+        'count' => 2,
+    ];
 }
 
 return $config;