[wpimath] Fix Debouncer type-changing behavior (#7870)

Closes #7867

Properly resets the baseline upon switching the debounce type, and adds
a test for such.

Signed-off-by: swurl <swurl@swurl.xyz>

wpimath/src/test/native/cpp/filter/DebouncerTest.cpp

@@ -72,4 +72,6 @@ TEST_F(DebouncerTest, DebounceParams) {
 
   EXPECT_TRUE(debouncer.GetDebounceType() ==
               frc::Debouncer::DebounceType::kFalling);
+
+  EXPECT_TRUE(debouncer.Calculate(false));
 }