Windows: Fix DLL build

There were a few "ambiguous operator new/delete" errors that were due to
inheriting from a private base class that used the leak detector. These
errors are resolved by adding the leak detector to the derived classes.

JUCE_API was missing from a few useful types, notably the ARA hosting
types.

modules/juce_product_unlocking/marketplace/juce_OnlineUnlockForm.cpp

@@ -45,6 +45,8 @@ struct Spinner final : public Component,
     {
         getLookAndFeel().drawSpinningWaitAnimation (g, Colours::darkgrey, 0, 0, getWidth(), getHeight());
     }
+
+    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Spinner)
 };
 
 struct OnlineUnlockForm::OverlayComp final : public Component,