Don't log the help text for screenrecord into the test log

It's really long and just noise, it looks like an error:

```
Feb 24, 2026 7:28:36 PM com.google.wireless.qa.mobileharness.shared.api.validator.env.AndroidHdVideoDecoratorEnvValidator validate
INFO: 'screenrecord --help' output: Usage: screenrecord [options] <filename>

Android screenrecord v1.4.  Records the device's display to a .mp4 file.

Options:
--size WIDTHxHEIGHT
    Set the video size, e.g. "1280x720".  Default is the device's main
    display resolution (if supported), 1280x720 if not.  For best results,
    use a size supported by the AVC encoder.
--bit-rate RATE
    Set the video bit rate, in bits per second.  Value may be specified as
    bits or megabits, e.g. '4000000' is equivalent to '4M'.  Default 20Mbps.
--bugreport
    Add additional information, such as a timestamp overlay, that is helpful
    in videos captured to illustrate bugs.
--time-limit TIME
    Set the maximum recording time, in seconds.  Default is 180. Set to 0
    to remove the time limit.
--display-id ID
    specify the physical display ID to record. Default is the primary display.
    see "dumpsys SurfaceFlinger --display-id" for valid display IDs.
--verbose
    Display interesting information on stdout.
--version
    Show Android screenrecord version.
--help
    Show this message.

Recording continues until Ctrl-C is hit or the time limit is reached.
```

PiperOrigin-RevId: 874918689

Author: mhansen

src/java/com/google/wireless/qa/mobileharness/shared/api/validator/env/AndroidHdVideoDecoratorEnvValidator.java

@@ -56,8 +56,7 @@ public void validate(Device device) throws MobileHarnessException, InterruptedEx
     }
     super.validate(device);
     try {
-      String output = adb.runShell(device.getDeviceId(), ADB_SHELL_VALIDATE);
-      logger.atInfo().log("'%s' output: %s", ADB_SHELL_VALIDATE, output);
+      String unused = adb.runShell(device.getDeviceId(), ADB_SHELL_VALIDATE);
     } catch (MobileHarnessException e) {
       logger.atWarning().log("Failed to run screenrecord: %s.", e.getMessage());
       throw new MobileHarnessException(