bitbox02: rm BitBox02Client.label override

if placeholder anyway, just use base impl
(alternatively we should list it in electrum.plugin.PLACEHOLDER_HW_CLIENT_LABELS)

electrum/plugins/bitbox02/bitbox02.py

@@ -68,9 +68,6 @@ class BitBox02Client(HardwareClientBase):
         if self.bitbox_hid_info is None:
             raise Exception("No BitBox02 detected")
 
-    def label(self) -> str:
-        return "BitBox02"
-
     def is_initialized(self) -> bool:
         return True