Exception inside ON_CALL will not be catched

Hi,

When I use ON_CALL with WillByDefault and try to throw exception inside it, that will not be catched by EXPECT_THROW. Also I am getting an error which says that exception was thrown during tests.

For example:

**MockClass**
```cpp
class MockClass : public SomeClass
{
public:
MOCK_METHOD(void, someFunction, (), (override);
}
```

**MockClassTests**
```cpp
TEST
{
MockClass mock;

ON_CALL(mock, someFunction).WillByDefault([]() {
throw std::runtime_error{"error message"};
});

EXPECT_THROW(mock.someFunction(), std::runtime_error);
}
```