SDK-2997: Add launch_platform_client method

tests/test_launch_platform_client.py

@@ -0,0 +1,17 @@
+import pytest
+
+from galaxy.unittest.mock import async_return_value
+
+from tests import create_message
+
+@pytest.mark.asyncio
+async def test_success(plugin, read):
+    request = {
+        "jsonrpc": "2.0",
+        "method": "launch_platform_client"
+    }
+
+    read.side_effect = [async_return_value(create_message(request)), async_return_value(b"")]
+    plugin.launch_platform_client.return_value = async_return_value(None)
+    await plugin.run()
+    plugin.launch_platform_client.assert_called_with()