fix(platform): show loading spinner only for selected plan, not all plans (#25290) (#25292)

## Problem
When users clicked on a plan card in the Cal.com Platform pricing UI, the loading
spinner would appear on ALL plan cards simultaneously instead of just the selected one.
This gave a confusing UX impression that all plans were being processed at the same time.

## Solution
Track the currently loading plan using a `loadingPlan` state variable that stores
which plan the user clicked on, rather than relying solely on the pending state from
the mutation hook.

## Changes
- Added `loadingPlan` state to track which specific plan is loading
- Update `loadingPlan` when a plan subscription is initiated
- Reset `loadingPlan` on error to ensure UI returns to normal state
- Modified `isLoading` prop condition to check if the current plan matches
  the `loadingPlan` before showing the spinner

This ensures that only the plan card the user clicked on displays the loading indicator,
while other plans remain in their normal state.

apps/web/components/settings/platform/pricing/platform-pricing/index.tsx

@@ -1,6 +1,7 @@
 import { useRouter } from "next/navigation";
 import { usePathname } from "next/navigation";
 import type { ReactNode } from "react";
+import { useState } from "react";
 
 import { ErrorCode } from "@calcom/lib/errorCodes";
 import { showToast } from "@calcom/ui/components/toast";
@@ -17,6 +18,8 @@ export const PlatformPricing = ({ teamId, teamPlan, heading }: PlatformPricingPr
   const pathname = usePathname();
   const currentPage = pathname?.split("/").pop();
   const router = useRouter();
+  const [loadingPlan, setLoadingPlan] = useState<string | null>(null);
+
   const { mutateAsync: createTeamSubscription, isPending: isCreateTeamSubscriptionLoading } =
     useSubscribeTeamToStripe({
       onSuccess: (redirectUrl: string) => {
@@ -24,6 +27,7 @@ export const PlatformPricing = ({ teamId, teamPlan, heading }: PlatformPricingPr
       },
       onError: () => {
         showToast(ErrorCode.UnableToSubscribeToThePlatform, "error");
+        setLoadingPlan(null);
       },
       teamId,
     });
@@ -35,6 +39,7 @@ export const PlatformPricing = ({ teamId, teamPlan, heading }: PlatformPricingPr
       },
       onError: () => {
         showToast(ErrorCode.UnableToSubscribeToThePlatform, "error");
+        setLoadingPlan(null);
       },
       teamId,
     });
@@ -44,6 +49,8 @@ export const PlatformPricing = ({ teamId, teamPlan, heading }: PlatformPricingPr
       return router.push("https://go.cal.com/quote");
     }
 
+    setLoadingPlan(plan);
+
     if (currentPage === "platform") {
       createTeamSubscription({ plan: plan.toLocaleUpperCase() });
     } else {
@@ -68,7 +75,10 @@ export const PlatformPricing = ({ teamId, teamPlan, heading }: PlatformPricingPr
                   description={plan.description}
                   pricing={plan.pricing}
                   includes={plan.includes}
-                  isLoading={isCreateTeamSubscriptionLoading || isUpgradeTeamSubscriptionLoading}
+                  isLoading={
+                    loadingPlan === plan.plan &&
+                    (isCreateTeamSubscriptionLoading || isUpgradeTeamSubscriptionLoading)
+                  }
                   currentPlan={plan.plan.toLocaleLowerCase() === teamPlan}
                   handleSubscribe={() => handleStripeSubscription(plan.plan)}
                 />