bitbox02: display amounts in sats if Electrum's base unit is sat

The BitBox02 has the ability to display all amounts in sats instead of
BTC. This was introduced in v9.13.0. If Electrum is configured to show
sats, we propagate this config to the BitBox02.

This is backwards compatible: users with older firmware will see the
values in BTC regardless of the config.

electrum/plugins/bitbox02/bitbox02.py

@@ -510,6 +510,12 @@ class BitBox02Client(HardwareClientBase):
                 )
 
         keypath_account = full_path[:-2]
+
+        format_unit = bitbox02.btc.BTCSignInitRequest.FormatUnit.DEFAULT
+        # Base unit is configured to be "sat":
+        if self.config.get_decimal_point() == 0:
+            format_unit = bitbox02.btc.BTCSignInitRequest.FormatUnit.SAT
+
         sigs = self.bitbox02_device.btc_sign(
             coin,
             [bitbox02.btc.BTCScriptConfigWithKeypath(
@@ -520,6 +526,7 @@ class BitBox02Client(HardwareClientBase):
             outputs=outputs,
             locktime=tx.locktime,
             version=tx.version,
+            format_unit=format_unit,
         )
 
         # Fill signatures