refactor(typesense): remove unused exists checks

In laravel#820 we introduced an exists check method, which then lead to static state issues as described in laravel#845

Those where addressed in laravel#846

But now that the function always double-checks the existence, we can remove the exists check entirely and only rely on the Typesense server response for this state.

This "fixes" issues where the server already has a collection and the client would try to recreate it. E.g. when it has flushed the index and another process or worker then creates the collection.

src/Engines/TypesenseEngine.php

@@ -497,26 +497,17 @@ public function deleteIndex($name)
     protected function getOrCreateCollectionFromModel($model, bool $indexOperation = true): TypesenseCollection
     {
         $method = $indexOperation ? 'indexableAs' : 'searchableAs';
+        $collectionName = $model->{$method}();
+        $collection = $this->typesense->getCollections()->{$collectionName};
 
-        $collection = $this->typesense->getCollections()->{$model->{$method}()};
-
-        $collectionExists = false;
-
-        if ($collection->exists()) {
-            // Also determine if the collection exists in Typesense...
-            $collectionName = $model->{$method}();
-
-            try {
-                $this->typesense->collections[$collectionName]->retrieve();
-
-                $collectionExists = true;
-            } catch (TypesenseClientError $e) {
-                //
-            }
-        }
+        // Determine if the collection exists in Typesense...
+        try {
+            $collection->retrieve();
 
-        if ($collectionExists) {
-            return $this->typesense->getCollections()->{$collectionName};
+            // No error means this exists on the server
+            return $collection
+        } catch (TypesenseClientError $e) {
+            //
         }
 
         $schema = config('scout.typesense.model-settings.'.get_class($model).'.collection-schema') ?? [];