fix: assign isInitialized: true at the end of .initialize() method (typeorm#9455)

Author: fraxken

src/data-source/DataSource.ts

@@ -234,9 +234,6 @@ export class DataSource {
         // connect to the cache-specific database if cache is enabled
         if (this.queryResultCache) await this.queryResultCache.connect()
 
-        // set connected status for the current connection
-        ObjectUtils.assign(this, { isInitialized: true })
-
         try {
             // build all metadatas registered in the current connection
             await this.buildMetadatas()
@@ -261,6 +258,9 @@ export class DataSource {
             throw error
         }
 
+        // set connected status for the current connection
+        ObjectUtils.assign(this, { isInitialized: true })
+
         return this
     }