Fix constraint conflict in LinkEmailElement

Fixed unsatisfiable constraints between ActivityIndicator and LinkMoreInfoView by replacing manual trailing constraint with UIStackView's setCustomSpacing API. This avoids conflicting with the stack view's internal UISV-spacing constraint.

Also removed LinkMoreInfoView from the broken constraints ignore list since the issue is now resolved.

Fixes: https://jira.corp.stripe.com/browse/RUN_MOBILESDK-4562
Committed-By-Agent: claude

Author: tillh-stripe

Example/PaymentSheet Example/PaymentSheet Example/AppDelegate+BrokenConstraints.swift

@@ -36,7 +36,6 @@ extension AppDelegate {
         // Ignore broken constraints that existed at the time of writing this - please try to fix newly introduced ones instead of ignoring!
         // Sometimes the broken constraint references something that is unique, in which case we can ignore it easily
         let ignoredBrokenConstraints = [
-            "STP_Internal_LinkMoreInfoView", // https://jira.corp.stripe.com/browse/RUN_MOBILESDK-4562
             "verticalSeparatorWidth' separator|.width == 0.333333", // Apple broken UIAlert constraint - oddly they never log this either; maybe they also have an ignorelist!
             "UISV-spacing' H:[_UIInterfaceActionCustomViewRepresentationView:", // Same as ^
             "_UIModernBarButton:", // iOS 26+ keyboard toolbar issue

StripePaymentSheet/StripePaymentSheet/Source/Internal/Link/Elements/LinkEmailElement.swift

@@ -42,8 +42,9 @@ class LinkEmailElement: Element {
             trailing: theme.textFieldInsets.trailing
         )
         if let infoView = infoView {
+            // Use stack view's custom spacing instead of manual constraints to avoid conflicts
+            stackView.setCustomSpacing(ElementsUI.contentViewInsets.trailing, after: activityIndicator)
             NSLayoutConstraint.activate([
-                activityIndicator.trailingAnchor.constraint(equalTo: infoView.leadingAnchor, constant: -ElementsUI.contentViewInsets.trailing),
                 infoView.widthAnchor.constraint(equalToConstant: LinkMoreInfoView.Constants.logoWidth),
             ])
         }