[Bug]: Copy for "site not connected" screen incorrect

### Describe the bug

@rachelcope using MM ext and saw this content on her screen. It's off-brand, redundant, and doesn't fit our content design style guidelines. It may also appear in Mobile and should be fixed there as well.

perhaps the pixel police team (aka @georgewrmarshall et al) can help?

### Expected behavior

Copy should read:

**MetaMask isn’t connected to this site**

To connect to a web3 site, find and click the connect button.

### Screenshots/Recordings


### Steps to reproduce

Tbh I'm not sure the exact steps to get to this stage, as I'm reporting on behalf of Rachel.

### Error messages or log output

```shell

```

### Detection stage

In production (default)

### Version

12.9.0

### Build type

None

### Browser

Chrome

### Operating system

MacOS

### Hardware wallet

_No response_

### Additional context

_No response_

### Severity

_No response_