fix (cherrypick): invoke_snap RPC requests inside the built-in browser (

#12928)

## **Description**

Cherry-pick of
d35a2a0
(#12923)

## **Related issues**

Fixes: https://infura.atlassian.net/issues/MDD-117 /
https://consensys.slack.com/archives/C027M10HGEA/p1736428038068929

## **Manual testing steps**

1. Visit this preview in the MM browser:
https://metamask-docs-git-snap-debugging-branch-consensys-ddffed67.vercel.app/developer-tools/faucet/
2. (optional) Press the "Debug Test" button, it should complete
3. Press the "Connect MetaMask" button, it should complete

## **Screenshots/Recordings**

<!-- If applicable, add screenshots and/or recordings to visualize the
before and after of your change. -->

### **Before**

<!-- [screenshots/recordings] -->

### **After**

<!-- [screenshots/recordings] -->

## **Pre-merge author checklist**

- [x] I’ve followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/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
- [x] I’ve applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/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.

app/core/Engine/Engine.ts

@@ -190,6 +190,8 @@ import {
 import { snapKeyringBuilder } from '../SnapKeyring';
 import { removeAccountsFromPermissions } from '../Permissions';
 import { keyringSnapPermissionsBuilder } from '../SnapKeyring/keyringSnapsPermissions';
+///: END:ONLY_INCLUDE_IF
+///: BEGIN:ONLY_INCLUDE_IF(preinstalled-snaps,external-snaps)
 import { HandleSnapRequestArgs } from '../Snaps/types';
 import { handleSnapRequest } from '../Snaps/utils';
 ///: END:ONLY_INCLUDE_IF