Check for analyzer rule names instead of descriptions in a flutter_tools test (#107541)

The descriptions can change between different versions of the analyzer.

Author: jason-simmons

packages/flutter_tools/test/integration.shard/analyze_once_test.dart

@@ -192,10 +192,10 @@ void main() {
       arguments: <String>['analyze', '--no-pub'],
       statusTextContains: <String>[
         'Analyzing',
-        'info $analyzerSeparator Avoid empty else statements',
-        'info $analyzerSeparator Avoid empty statements',
-        "info $analyzerSeparator The declaration '_incrementCounter' isn't",
-        "warning $analyzerSeparator The parameter 'onPressed' is required",
+        'avoid_empty_else',
+        'empty_statements',
+        'unused_element',
+        'missing_required_param',
       ],
       exitMessageContains: '4 issues found.',
       exitCode: 1,