MC-5824: Remove data migration from main Page Builder module

- Fix introduction of string type within converter

Author: davemacaulay

app/code/Magento/PageBuilderDataMigration/Setup/DataConverter/BlueFootToPageBuilder.php

@@ -48,7 +48,7 @@ public function __construct(
      * @param string $value
      * @return string
      */
-    public function convert(string $value)
+    public function convert($value)
     {
         if (preg_match('/<!--' . Format::BLUEFOOT_KEY . '="(.*)"-->/', $value, $matches)) {
             if ($this->validator->validate($matches[1])) {

app/code/Magento/PageBuilderDataMigration/Setup/DataConverter/MixedToPageBuilder.php

@@ -47,7 +47,7 @@ public function __construct(
      * @param string $value
      * @return string
      */
-    public function convert(string $value)
+    public function convert($value)
     {
         if (strstr($value, Format::UNMIGRATED_KEY) !== false) {
             return $this->convertMixed($value);