feat(STX-325): remove STX status page (#38460)

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## **Description**

This PR removes the smart transaction status page from the transaction
submission flow

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## **Changelog**

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CHANGELOG entry: remove smart transaction status page

## **Related issues**

Relates to: https://consensyssoftware.atlassian.net/browse/STX-325

## **Manual testing steps**


## **Screenshots/Recordings**

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### **Before**

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### **After**

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## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask
Extension Coding
Standards](https://github.com/MetaMask/metamask-extension/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I’ve included tests if applicable
- [x] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-extension/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **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.


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Introduces `extensionSkipSmartTransactionStatusPage` flag, updates
smart-transaction flow to honor it, enhances remote flag merging, and
adds focused tests.
> 
> - **Smart Transactions flow**
> - Add `extensionSkipSmartTransactionStatusPage` to feature flags and
use it to force `shouldShowStatusPage` to `false`; otherwise retain
existing type-based/batch logic.
> - Log `shouldShowStatusPage` value; no change to non-STX or legacy
fallbacks.
> - **Selectors**
> - Extend `SmartTransactionNetwork` and `getFeatureFlagsByChainId` to
include `extensionSkipSmartTransactionStatusPage`.
> - Implement merged remote flag precedence: chain-specific > default >
hardcoded defaults.
> - **Tests**
> - Add/expand cases validating status-page visibility across
transaction types, batch submissions, and the new skip flag
(true/false/undefined).
> - Update feature-flag selector tests to cover remote overrides and new
flag defaults.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
6c31127. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: rarquevaux