Android: Simplify SDK setup process by minimizing number of dialogs

SDK setup process currently downloads the SDK tools, then checks
the mandatory packages, asks the user if they want to install them,
then show a dialog with package details, then asks again whether
the user wants to check the licenses.

The following two steps are redundant because there's a dialog which
guards the package installation and waits for user's input:
* Asking the user if they want to install the mandatory packages
* Asking the user if they want to verify the licenses

Change-Id: If06c0adea9444107a149c3ec32be67061954d1bb
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/android/androidsdkmanagerwidget.h

@@ -80,7 +80,7 @@ public:
                             QWidget *parent = nullptr);
     ~AndroidSdkManagerWidget() override;
 
-    void installEssentials();
+    void installEssentials(const QString &extraMessage = {});
 
 signals:
     void updatingSdk();
@@ -88,7 +88,7 @@ signals:
     void licenseWorkflowStarted();
 
 private:
-    void onApplyButton();
+    void onApplyButton(const QString &extraMessage = {});
     void onUpdatePackages();
     void onCancel();
     void onOperationResult(int index);