Encode device parameter before channel retrieval

Fixed an issue in the `get_channels_for_device` function where the input
device name wasn't being encoded before passing it to the underlying C
function `getChannelsFromInfo`. This change ensures compatibility with
the expected string encoding, preventing potential runtime errors
related to string handling across the Python-C boundary.

Author: thekumi

src/limedriver/limedriver.pyx

@@ -724,5 +724,5 @@ def get_device_list():
     return [device.decode('utf-8') for device in devices] 
 
 def get_channels_for_device(device = ""):
-    cdef pair[int, int] channels = getChannelsFromInfo(device)
+    cdef pair[int, int] channels = getChannelsFromInfo(device.encode())
     return channels.first, channels.second