sweep: improve loggings based on feedback

This commit changes the logging levels and add a few more loggings based
on the testing results from the testnet/mainnet.

sweep/sweeper_test.go

@@ -695,12 +695,12 @@ func TestSweepPendingInputs(t *testing.T) {
 
 	// Mock the methods used in `sweep`. This is not important for this
 	// unit test.
-	setNeedWallet.On("Inputs").Return(nil).Times(4)
+	setNeedWallet.On("Inputs").Return(nil).Maybe()
 	setNeedWallet.On("DeadlineHeight").Return(testHeight).Once()
 	setNeedWallet.On("Budget").Return(btcutil.Amount(1)).Once()
 	setNeedWallet.On("StartingFeeRate").Return(
 		fn.None[chainfee.SatPerKWeight]()).Once()
-	normalSet.On("Inputs").Return(nil).Times(4)
+	normalSet.On("Inputs").Return(nil).Maybe()
 	normalSet.On("DeadlineHeight").Return(testHeight).Once()
 	normalSet.On("Budget").Return(btcutil.Amount(1)).Once()
 	normalSet.On("StartingFeeRate").Return(