test: Bump recentZulipFeatureLevel to FL 382, from FL 278

To make sure that recentZulipFeatureLevel is both recent and
reasonable, the new value is taken from the changelog, at the
time this was committed:
  https://github.com/zulip/zulip/blob/c6660fbea/api_docs/changelog.md?plain=1#L23

As a result, this assumes support for empty topics in our app code.

To make sure we are aware of possible behavior changes in the app
code we test against.  Here's a helpful `git grep` command and its result
(thanks to "zulipFeatureLevel" being quite a greppable name):

```
$ git grep 'zulipFeatureLevel [<>]' lib
lib/api/model/narrow.dart:  final supportsOperatorDm = zulipFeatureLevel >= 177; // TODO(server-7)
lib/api/model/narrow.dart:  final supportsOperatorWith = zulipFeatureLevel >= 271; // TODO(server-9)
lib/model/autocomplete.dart:        final isChannelWildcardAvailable = store.zulipFeatureLevel >= 247; // TODO(server-9)
lib/model/autocomplete.dart:    final isTopicWildcardAvailable = store.zulipFeatureLevel >= 224; // TODO(server-8)
lib/model/compose.dart:  final isChannelWildcardAvailable = store.zulipFeatureLevel >= 247; // TODO(server-9)
lib/model/compose.dart:  final isTopicWildcardAvailable = store.zulipFeatureLevel >= 224; // TODO(server-8)
lib/model/store.dart:    if (zulipFeatureLevel >= 163) { // TODO(server-7)
lib/model/store.dart:  bool get isUnsupported => zulipFeatureLevel < kMinSupportedZulipFeatureLevel;
lib/widgets/action_sheet.dart:  final supportsUnmutingTopics = store.zulipFeatureLevel >= 170;
lib/widgets/action_sheet.dart:  final supportsFollowingTopics = store.zulipFeatureLevel >= 219;
lib/widgets/action_sheet.dart:  final markAsUnreadSupported = store.zulipFeatureLevel >= 155; // TODO(server-6)
lib/widgets/actions.dart:    final useLegacy = store.zulipFeatureLevel < 155; // TODO(server-6)
lib/widgets/actions.dart:    assert(PerAccountStoreWidget.of(context).zulipFeatureLevel >= 155); // TODO(server-6)
lib/widgets/autocomplete.dart:    final isChannelWildcardAvailable = store.zulipFeatureLevel >= 247; // TODO(server-9)
lib/widgets/compose_box.dart:    if (store.zulipFeatureLevel < 334) {
lib/widgets/compose_box.dart:    if (store.zulipFeatureLevel >= 334) {
```

We can tell that this bump only affects 2 entries from above:

```
lib/widgets/compose_box.dart:    if (store.zulipFeatureLevel < 334) {
lib/widgets/compose_box.dart:    if (store.zulipFeatureLevel >= 334) {
```

All are related to the FL 334 (general chat) changes.

Author: PIG208

test/example_data.dart

@@ -77,7 +77,7 @@ final Uri realmUrl = Uri.parse('https://chat.example/');
 Uri get _realmUrl => realmUrl;
 
 const String recentZulipVersion = '9.0';
-const int recentZulipFeatureLevel = 278;
+const int recentZulipFeatureLevel = 382;
 const int futureZulipFeatureLevel = 9999;
 const int ancientZulipFeatureLevel = kMinSupportedZulipFeatureLevel - 1;