fix(core): Use popup sign in as the default behavior

Author: Ehesp

packages/core/src/behaviors/index.test.ts

@@ -22,6 +22,10 @@ vi.mock("./require-display-name", () => ({
 
 vi.mock("firebase/auth", () => ({
   RecaptchaVerifier: vi.fn(),
+  signInWithPopup: vi.fn(),
+  linkWithPopup: vi.fn(),
+  signInWithRedirect: vi.fn(),
+  linkWithRedirect: vi.fn(),
 }));
 
 beforeEach(() => {

packages/core/src/behaviors/index.ts

@@ -126,6 +126,6 @@ export function getBehavior<T extends keyof Registry>(ui: FirebaseUI, key: T): R
 
 export const defaultBehaviors: Behavior<"recaptchaVerification"> = {
   ...recaptchaVerification(),
-  ...providerRedirectStrategy(),
+  ...providerPopupStrategy(),
   ...countryCodes(),
 };