Bug 1091486 - [SMS] Switch to MMS when entering a email recipient thread

typo: ```Utils.isEmailAddress(recipients);``` ----> ```Utils.isEmailAddress(recipient);```, but since ```Utils.isEmailAddress``` doesn't have any context dependencies we can just use:
```
var hasEmailRecipient = recipients.some(Utils.isEmailAddress);
 // or even use it directly with variable in the expression below - up to you
```