Release Edge callbacks after registering

[amartya4256]

This PR releases the HandleCoreWebView2SwtCallback resource created by Edge browser in createControllerInitializationCallback after it has been registered by CreateCoreWebView2Controller method as otherwise the HandleCoreWebView2SwtCallback object can cause memory leaks if left unreleased.

fixes #2339

How to test:

1. On master, test this snippet:

package org.eclipse.swt.snippets;

import org.eclipse.swt.*;
import org.eclipse.swt.browser.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

public class Snippet138 {
	public static void main(String[] args) {
		Display display = new Display();
		Shell parentShell = new Shell(display);
		long allocatedMemory =  (Runtime.getRuntime().totalMemory()-Runtime.getRuntime().freeMemory());
		long presumableFreeMemory = Runtime.getRuntime().maxMemory() - allocatedMemory;
		long blockSize = Math.min(Integer.MAX_VALUE / 2, presumableFreeMemory/10);
		int block = Math.toIntExact(blockSize);

		for(int i = 0; i < 100; i++) { // should not fail after 5 rounds

		    Shell shell = new Shell(parentShell);
		    Browser browser = new Browser(shell, SWT.BORDER);
		    shell.setLayout(new RowLayout());
		    browser.setUrl("http://example.com");
		    browser.setSize(500, 500);

		    shell.open();

		    browser.addTitleListener(new TitleListener() {

		        byte[] payload = new byte[block];

		        @Override
		        public void changed(TitleEvent event) {
		            System.out.println(payload[0]); // reference payload
		        }
		    });

		    shell.close();
		    browser.dispose();
		    browser = null;
		    shell=null;

		}
	}
}

It should throw an out of memory exception.
2. Run the snippet on this branch. The code should execute without any exception.

[github-actions]

Test Results

   546 files  ±0     546 suites  ±0   29m 49s ⏱️ + 2m 7s
 4 412 tests ±0   4 395 ✅ ±0   17 💤 ±0  0 ❌ ±0 
16 718 runs  ±0  16 591 ✅ ±0  127 💤 ±0  0 ❌ ±0 

Results for commit 8b36722. ± Comparison against base commit bcc58ad.

[fedejeanne]

LGTM, thank you @amartya4256 !

I changed the snippet a little since it didn't work on my machine (there was an ArithmethicException when calling Math::toIntExact)