Updated integration_tests/platform_interaction test_step.dart (#131301)

Force the line height of the TextStyle used in test_step.dart to be 1.0 for all Text widgets.

The test started failing after https://github.com/flutter/flutter/pull/129724 landed. Assuming that the vertical layout of the test was tight and that the change in the default font's line height is the source of the problem (see https://github.com/flutter/flutter/issues/130732#issuecomment-1639089638).

Fixes https://github.com/flutter/flutter/issues/130732

dev/integration_tests/platform_interaction/lib/src/test_step.dart

@@ -37,7 +37,8 @@ class TestStepResult {
   final String description;
   final TestStatus status;
 
-  static const TextStyle bold = TextStyle(fontWeight: FontWeight.bold);
+  static const TextStyle normal = TextStyle(height: 1.0);
+  static const TextStyle bold = TextStyle(fontWeight: FontWeight.bold, height: 1.0);
   static const TestStepResult complete = TestStepResult(
     'Test complete',
     nothing,
@@ -49,8 +50,8 @@ class TestStepResult {
       crossAxisAlignment: CrossAxisAlignment.start,
       children: <Widget>[
         Text('Step: $name', style: bold),
-        Text(description),
-        const Text(' '),
+        Text(description, style: normal),
+        const Text(' ', style: normal),
         Text(
           status.toString().substring('TestStatus.'.length),
           key: ValueKey<String>(