Dashboard: use BuyWidget instead of CheckoutWidget in TransactionButton (#7857)

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## PR-Codex overview
This PR focuses on updating the `MismatchButton` component by replacing the `CheckoutWidget` with the `BuyWidget`, streamlining the payment interface.

### Detailed summary
- Replaced `CheckoutWidget` with `BuyWidget` in the render method of the `MismatchButton` component.
- Removed the `name` and `seller` props from the `BuyWidget`.

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<!-- This is an auto-generated comment: release notes by coderabbit.ai -->

## Summary by CodeRabbit

* New Features
  * Introduced a new Buy experience in the pay dialog for adding funds.

* Improvements
  * Streamlined purchase flow with fewer required inputs and a cleaner interface.
  * Pay dialog can be opened and initiated without first connecting a wallet/account.
  * Consistent styling and theming applied across the new purchase widget.

* Chores
  * Updated dependencies to use the latest purchase widget component.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: MananTank

apps/dashboard/src/@/components/tx-button/MismatchButton.tsx

@@ -18,7 +18,7 @@ import {
 } from "thirdweb";
 import { type Chain, type ChainMetadata, localhost } from "thirdweb/chains";
 import {
-  CheckoutWidget,
+  BuyWidget,
   useActiveAccount,
   useActiveWallet,
   useActiveWalletChain,
@@ -267,14 +267,12 @@ export const MismatchButton = forwardRef<
             />
           )}
 
-          {dialog === "pay" && account && (
-            <CheckoutWidget
+          {dialog === "pay" && (
+            <BuyWidget
               className="!w-full"
               client={props.client}
               chain={txChain}
               amount="0.01"
-              name="Buy Funds"
-              seller={account.address as `0x${string}`}
               theme={getSDKTheme(theme === "dark" ? "dark" : "light")}
             />
           )}