Bluetooth: fix send_string in HID client

The send_string method is broken after the change crrev/c/6097109.
This corrects the change to the equivalent behavior.

BUG=b:393170781
TEST=run bluetooth_WiFiCoexPerformance.ble_keyboard_load.11n.floss

Change-Id: I4bf5b9dd3411b431a9b78034ac77c67b46658542
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/chameleon/+/6917163
Commit-Queue: Yun-hao Chung <[email protected]>
Reviewed-by: Zhengping Jiang <[email protected]>
Tested-by: Yun-hao Chung <[email protected]>
1 file changed