AC-1989: Fix subset of deprecated php usages

- Fixes for CR

Author: Rrego6

app/code/Magento/Cron/Model/Config/Converter/Db.php

@@ -92,7 +92,8 @@ protected function _processScheduleParam(array $jobConfig, $jobName, array &$res
     protected function _processRunModel(array $jobConfig, $jobName, array &$result)
     {
         if (isset($jobConfig['run']) && is_array($jobConfig['run']) && array_key_exists('model', $jobConfig['run'])) {
-            $callPath = explode('::', $jobConfig['run']['model'] ?? '');
+            $runModel = $jobConfig['run']['model'];
+            $callPath = $runModel ? explode('::', $runModel) : [];
 
             if (empty($callPath) || empty($callPath[0]) || empty($callPath[1])) {
                 unset($result[$jobName]['run']);

app/code/Magento/CurrencySymbol/Block/Adminhtml/System/Currency/Rate/Matrix.php

@@ -107,7 +107,7 @@ protected function _prepareRates($array)
 
         foreach ($array as $key => $rate) {
             foreach ($rate as $code => $value) {
-                $parts = explode('.', $value ?? '');
+                $parts = $value !== null ? explode('.', $value) : [];
                 if (count($parts) == 2) {
                     $parts[1] = str_pad(rtrim($parts[1], 0), 4, '0', STR_PAD_RIGHT);
                     $array[$key][$code] = join('.', $parts);

app/code/Magento/MediaStorage/App/Media.php

@@ -238,8 +238,12 @@ private function createLocalCopy(): void
      */
     private function checkMediaDirectoryChanged(): bool
     {
-        return rtrim($this->mediaDirectoryPath ?? '', '/')
-            !== rtrim($this->directoryMedia->getAbsolutePath() ?? '', '/');
+        $isDirectoryChanged = false;
+        if ($this->mediaDirectoryPath && $this->directoryMedia->getAbsolutePath()) {
+            $isDirectoryChanged = rtrim($this->mediaDirectoryPath, '/')
+                !== rtrim($this->directoryMedia->getAbsolutePath(), '/');
+        }
+        return $isDirectoryChanged;
     }
 
     /**

app/code/Magento/Newsletter/Block/Adminhtml/Template/Edit.php

@@ -216,7 +216,8 @@ public function getForm()
      */
     public function getJsTemplateName()
     {
-        return addcslashes($this->getModel()->getTemplateCode() ?? '', "\"\r\n\\");
+        $templateCode = $this->getModel()->getTemplateCode();
+        return $templateCode ? addcslashes($templateCode, "\"\r\n\\") : '';
     }
 
     /**

app/code/Magento/SalesRule/Model/Quote/Discount.php

@@ -293,10 +293,10 @@ public function fetch(Quote $quote, Total $total)
         $amount = $total->getDiscountAmount();
 
         if ($amount != 0) {
-            $description = $total->getDiscountDescription();
+            $description = $total->getDiscountDescription() ?? '';
             $result = [
                 'code' => $this->getCode(),
-                'title' => strlen($description ?? '') ? __('Discount (%1)', $description) : __('Discount'),
+                'title' => strlen($description) ? __('Discount (%1)', $description) : __('Discount'),
                 'value' => $amount
             ];
         }

lib/internal/Magento/Framework/App/Utility/Files.php

@@ -1661,9 +1661,8 @@ public function isModuleExists($moduleName)
     {
         $key = __METHOD__ . "/{$moduleName}";
         if (!isset(self::$_cache[$key])) {
-            self::$_cache[$key] = file_exists(
-                $this->componentRegistrar->getPath(ComponentRegistrar::MODULE, $moduleName) ?? ''
-            );
+            $componentPath = $this->componentRegistrar->getPath(ComponentRegistrar::MODULE, $moduleName);
+            self::$_cache[$key] = $componentPath && file_exists($componentPath);
         }
 
         return self::$_cache[$key];