Add restriction on tab opening to the current active tab

In the existing extension, any tab initiating a PrivateToken request for
a trusted issuer is going to trigger the associated attester tab
opening. This might interrupt the user flow.
This commit introduces an improvement to only allow the current active
tab to open a new tab upon a PrivateToken request.

src/background/index.ts

@@ -64,6 +64,16 @@ export const headerToToken = async (
             // API expects interactive Challenge at /challenge
             attesterURI = `${attesterURI}/challenge`;
 
+            // To minimize the number of tabs opened, we check if the requesting tab is the active tab
+            const activeTab: number | undefined = await new Promise((resolve) =>
+                chrome.tabs.query({ active: true, currentWindow: true }, (tabs) =>
+                    resolve(tabs[0].id),
+                ),
+            );
+            if (activeTab !== tabId) {
+                logger.debug('Not openning a new tab due to requesting tab not being active');
+                return undefined;
+            }
             const tab: chrome.tabs.Tab = await new Promise((resolve) =>
                 chrome.tabs.create({ url: attesterURI }, resolve),
             );