fix: flaky payment-details test with Stripe iframe waits

[sahitya-chandra]

Issue: #1531

Test:

• e2e/tests/settings/administrator/payment-details.spec.ts:22:3 › Company administrator settings - payment details › allows connecting a bank account
  https://github.com/antiwork/flexile/actions/runs/20915820205/job/60089005090#step:12:270

Problem

The test was timing out because:

1. The Stripe iframe (elements-inner-payment) loads asynchronously from an external CDN
2. The test clicked "Test Institution" immediately without waiting for the iframe content to render
3. In CI, the iframe often wasn’t ready within the timeout

Solution

Added implicit waits before each Stripe iframe interaction:

• await expect(stripePaymentFrame.getByLabel("Test Institution")).toBeVisible(); before clicking "Test Institution" in both the initial "Link your bank account" flow and the "Edit" flow

This follows the same pattern used in the microdeposits test in the same file (waiting for "Routing number" before interacting with the bank frame).

Screenshot

couldn't able to test this locally because I don't have a Stripe account currently.
So, I am relying on CI checks for this test verification.

AI Disclosure

I have used Claude Opus 4.5 to implement the fix.

[sahitya-chandra]

@nyomanjyotisa _a could you review this pr?

All CI checks have passed...

[nyomanjyotisa]

Test failing: