Fix Connect JS alert after destroyed activity

[gimenete-stripe]

Summary

Fix StripeConnectWebView JS alert handling when the host activity has already been destroyed.

Motivation

StripeConnectWebChromeClient.handleJsAlert could call AlertDialog.show() after the host activity was destroyed, which can throw WindowManager.BadTokenException and crash the host app.

This guards alert handling on a live ComponentActivity, cancels the pending JS result when the activity is unavailable, and catches BadTokenException as a final defensive fallback so the WebView callback is not left hanging.

RUN_MXMOBILE-16866

Testing

• Added tests
• Modified tests: updated PaymentMethodEndToEndTest.kt to match current Bancontact API behavior when billing_details[name] is omitted.

JAVA_HOME=/Applications/Android\ Studio.app/Contents/jbr/Contents/Home timeout 600 ./gradlew :connect:testDebugUnitTest --tests com.stripe.android.connect.webview.StripeConnectWebViewTest

JAVA_HOME=/Applications/Android\ Studio.app/Contents/jbr/Contents/Home timeout 600 ./gradlew :payments-core:testDebugUnitTest --tests com.stripe.android.PaymentMethodEndToEndTest.createPaymentMethod_withBancontact_missingName_shouldCreateObject

Screenshots

N/A

Changelog

N/A

[maragues-stripe]

LGTM 👌

[gimenete-stripe]

r? @maragues-stripe can you re-approve? There were some flaky tests unrelated to my changes and I updated the workflow file to debug them, but finally all tests passed. I think it's worth keeping the workflow file changes though.