[10.x] Combine prefix with table for compileDropPrimary PostgreSQL (#48268)

* Combine prefix with table

* StyleCI fix

Author: dyriavin

src/Illuminate/Database/Schema/Blueprint.php

@@ -1785,6 +1785,16 @@ public function getTable()
         return $this->table;
     }
 
+    /**
+     * Get the table prefix.
+     *
+     * @return string
+     */
+    public function getPrefix()
+    {
+        return $this->prefix;
+    }
+
     /**
      * Get the columns on the blueprint.
      *

src/Illuminate/Database/Schema/Grammars/PostgresGrammar.php

@@ -427,7 +427,7 @@ public function compileDropColumn(Blueprint $blueprint, Fluent $command)
      */
     public function compileDropPrimary(Blueprint $blueprint, Fluent $command)
     {
-        $index = $this->wrap("{$blueprint->getTable()}_pkey");
+        $index = $this->wrap("{$blueprint->getPrefix()}{$blueprint->getTable()}_pkey");
 
         return 'alter table '.$this->wrapTable($blueprint)." drop constraint {$index}";
     }