Invalid `wallet_requestSnaps` and `wallet_invokeSnap` specs

`wallet_requestSnaps` and `wallet_invokeSnap` use an object as params, but on the docs, the params are currently being wrapped in an array.

The spec and examples should be updated to use this format:

### `wallet_requestSnaps`

```ts
type Request = {
method: 'wallet_requestSnaps';
params: Record;
}
```

### `wallet_invokeSnap`

```ts
type Request = {
method: 'wallet_invokeSnap',
params: {
snapId: SnapId;
request: {
method: string;
params: Json;
}
}
}
```

Search the repository for the wallet_requestSnaps and wallet_invokeSnap specs and examples. Update each params definition and example so params is an object rather than an array, matching the TypeScript shapes in the issue. Done means both methods consistently use the corrected object format.

Written by the indexing model from the issue text.