FEAT: Update what's new and settings copy to communicate additional network coverage on extension (#22618)

## **Description**
- What's new copy should be updated to:
> Steer clear of known scams while still preserving your privacy with
security alerts powered by Blockaid. This feature is available on
Arbitrum, Avalanche, BNB chain, Ethereum Mainnet, Linea, Optimism and
Polygon.
> 
> Always do your own due diligence before approving requests.

- Settings copy should be updated to:
> Privacy preserving - no data is shared with third parties. Available
on Arbitrum, Avalanche, BNB chain, Ethereum Mainnet, Linea, Optimism and
Polygon.

## **Related issues**

Fixes:
[#1695](MetaMask/MetaMask-planning#1695)

Blocked By: #22070 

## **Screenshots/Recordings**

### **Before**


https://github.com/MetaMask/metamask-extension/assets/44811/0e6b6103-efb0-4ed8-94c2-44ac0f281ff8

### **After**


https://github.com/MetaMask/metamask-extension/assets/44811/36740992-0af2-44c5-b62b-0ac522df4d17

## **Pre-merge author checklist**

- [x] I’ve followed [MetaMask Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've clearly explained what problem this PR is solving and how it
is solved.
- [x] I've linked related issues
- [x] I've included manual testing steps
- [x] I've included screenshots/recordings if applicable
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/develop/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.
- [x] I’ve properly set the pull request status:
  - [ ] In case it's not yet "ready for review", I've set it to "draft".
- [x] In case it's "ready for review", I've changed it from "draft" to
"non-draft".

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

Author: segun

app/_locales/en/messages.json

@@ -495,9 +495,8 @@ export const getTranslatedUINotifications = (
       description: [
         t('notificationsBlockaidDefaultDescriptionOne'),
         t('notificationsBlockaidDefaultDescriptionTwo'),
-        t('notificationsBlockaidDefaultDescriptionThree'),
       ],
-      actionText: t('notificationsBlockaidDefaultDescriptionThreeActionText'),
+      actionText: t('notificationsBlockaidDefaultDescriptionActionText'),
       date: UI_NOTIFICATIONS[NOTIFICATION_BLOCKAID_DEFAULT].date
         ? new Intl.DateTimeFormat(formattedLocale).format(
             new Date(UI_NOTIFICATIONS[NOTIFICATION_BLOCKAID_DEFAULT].date),

shared/notifications/index.js

@@ -57,7 +57,7 @@ exports[`ExperimentalTab with desktop enabled renders ExperimentalTab component
             <h6
               class="mm-box mm-text mm-text--body-sm mm-box--margin-top-0 mm-box--margin-right-1 mm-box--color-text-alternative"
             >
-              Privacy preserving - no data is shared with third parties. Available on Ethereum Mainnet.
+              Privacy preserving - no data is shared with third parties. Available on Arbitrum, Avalanche, BNB chain, Ethereum Mainnet, Linea, Optimism and Polygon.
             </h6>
           </div>
           <label