Content and UI updates for the STX modal (#13798)

* Update content and UI for STX modal

* Update the main header image for STX

* Capitalize Smart Transactions in the button label

app/_locales/en/messages.json

@@ -1014,7 +1014,7 @@
     "message": "Use OpenSea's API to fetch NFT data. NFT auto-detection relies on OpenSea's API, and will not be available when this is turned off."
   },
   "enableSmartTransactions": {
-    "message": "Enable smart transactions"
+    "message": "Enable Smart Transactions"
   },
   "enableToken": {
     "message": "enable $1",
@@ -2949,19 +2949,19 @@
     "message": "Store this phrase in a password manager like 1Password."
   },
   "stxAreHere": {
-    "message": "Smart transactions are here!"
+    "message": "Smart Transactions are here!"
   },
   "stxBenefit1": {
-    "message": "Decrease transaction costs"
+    "message": "Minimize transaction costs"
   },
   "stxBenefit2": {
-    "message": "Reduce failures & minimize costs"
+    "message": "Reduce transaction failures"
   },
   "stxBenefit3": {
-    "message": "Protect from front-running"
+    "message": "Eliminate stuck transactions"
   },
   "stxBenefit4": {
-    "message": "Eliminate stuck transactions"
+    "message": "Prevent front-running"
   },
   "stxCancelled": {
     "message": "Swap would have failed"
@@ -2973,7 +2973,7 @@
     "message": "Try your swap again. We’ll be here to protect you against similar risks next time."
   },
   "stxDescription": {
-    "message": "Smart transactions use MetaMask smart contracts to simulate transactions before submitting in order to..."
+    "message": "MetaMask Swaps just got a whole lot smarter! Enabling Smart Transactions will allow MetaMask to programmatically optimize your Swap to help:"
   },
   "stxFailure": {
     "message": "Swap failed"
@@ -2995,7 +2995,7 @@
     "message": "Privately submitting the Swap..."
   },
   "stxSubDescription": {
-    "message": "Enabling allows MetaMask to simulate transactions, proactively cancel bad transactions and sign MetaMask Swaps transactions for you."
+    "message": "* Smart Transactions will attempt to submit your transaction privately, multiple times. If all attempts fail, the transaction will be broadcast publicly to ensure your Swap successfully goes through."
   },
   "stxSuccess": {
     "message": "Swap complete!"

ui/pages/swaps/build-quote/build-quote.js

@@ -595,23 +595,32 @@ export default function BuildQuote({
                 flexDirection={FLEX_DIRECTION.COLUMN}
               >
                 <img
-                  src="./images/logo/metamask-smart-transactions@4x.png"
+                  src="./images/logo/smart-transactions-header.png"
                   alt={t('swapSwapSwitch')}
                 />
               </Box>
-              <Typography variant={TYPOGRAPHY.H6} marginTop={0}>
+              <Typography variant={TYPOGRAPHY.H7} marginTop={0}>
                 {t('stxDescription')}
               </Typography>
               <Typography
                 tag="ul"
-                variant={TYPOGRAPHY.H6}
+                variant={TYPOGRAPHY.H7}
                 fontWeight={FONT_WEIGHT.BOLD}
                 marginTop={3}
               >
                 <li>{t('stxBenefit1')}</li>
                 <li>{t('stxBenefit2')}</li>
                 <li>{t('stxBenefit3')}</li>
-                <li>{t('stxBenefit4')}</li>
+                <li>
+                  {t('stxBenefit4')}
+                  <Typography
+                    tag="span"
+                    fontWeight={FONT_WEIGHT.NORMAL}
+                    variant={TYPOGRAPHY.H7}
+                  >
+                    {' *'}
+                  </Typography>
+                </li>
               </Typography>
               <Typography
                 variant={TYPOGRAPHY.H8}