Set the global default adb mode to vsock_half_tunnel.

Test: Run with -vm_manager=crosvm, -vm_manager=qemu_cli
Bug: 130565669
Change-Id: Ia5e1fc4dc1062580daec803efef3679fae28dbd2
(cherry picked from commit 1074333b007da0126a9b828ab75877946fdd2ed0)
diff --git a/host/commands/launch/flags.cc b/host/commands/launch/flags.cc
index 1387f30..d1d7d21 100644
--- a/host/commands/launch/flags.cc
+++ b/host/commands/launch/flags.cc
@@ -124,7 +124,7 @@
 DEFINE_string(socket_vsock_proxy_binary,
               vsoc::DefaultHostArtifactsPath("bin/socket_vsock_proxy"),
               "Location of the socket_vsock_proxy binary.");
-DEFINE_string(adb_mode, "",
+DEFINE_string(adb_mode, "vsock_half_tunnel",
               "Mode for ADB connection. Can be 'usb' for USB forwarding, "
               "'tunnel' for a TCP connection tunneled through VSoC, "
               "'vsock_tunnel' for a TCP connection tunneled through vsock, "
@@ -472,8 +472,6 @@
                                google::FlagSettingMode::SET_FLAGS_DEFAULT);
   SetCommandLineOptionWithMode("hardware_name", "cutf_ivsh",
                                google::FlagSettingMode::SET_FLAGS_DEFAULT);
-  SetCommandLineOptionWithMode("adb_mode", "tunnel",
-                               google::FlagSettingMode::SET_FLAGS_DEFAULT);
   SetCommandLineOptionWithMode("decompress_kernel", "false",
                                google::FlagSettingMode::SET_FLAGS_DEFAULT);
   SetCommandLineOptionWithMode("logcat_mode", cvd::kLogcatSerialMode,
@@ -500,8 +498,6 @@
                                google::FlagSettingMode::SET_FLAGS_DEFAULT);
   SetCommandLineOptionWithMode("hardware_name", "cutf_cvm",
                                google::FlagSettingMode::SET_FLAGS_DEFAULT);
-  SetCommandLineOptionWithMode("adb_mode", "vsock_tunnel",
-                               google::FlagSettingMode::SET_FLAGS_DEFAULT);
   SetCommandLineOptionWithMode("decompress_kernel", "true",
                                google::FlagSettingMode::SET_FLAGS_DEFAULT);
   SetCommandLineOptionWithMode("run_e2e_test", "false",