Fix lifecycle issue in DTDManager (#9200)

* Fix lifecycle issue in DtdManager

* changelog

Author: kenzieschmoll

packages/devtools_app_shared/CHANGELOG.md

@@ -10,6 +10,7 @@ getter.
 `package:devtools_app_shared/service.dart` library to the 
 `package:devtools_app_shared/utils.dart` library.
 * Fix alignment issues in `DevToolsClearableTextField`.
+* Fix a lifecycle issue with `DTDManager`.
 
 ## 0.3.1
 * Bump `vm_service` dependency to `>=13.0.0 <16.0.0`.

packages/devtools_app_shared/lib/src/service/dtd_manager.dart

@@ -33,8 +33,11 @@ class DTDManager {
     await disconnect();
 
     try {
-      _connection.value = await DartToolingDaemon.connect(uri);
+      final connection = await DartToolingDaemon.connect(uri);
       _uri = uri;
+      // Set this after setting the value of [_uri] so that [_uri] can be used
+      // by any listeners of the [_connection] notifier.
+      _connection.value = connection;
       _log.info('Successfully connected to DTD at: $uri');
     } catch (e, st) {
       onError?.call(e, st);