FTUE problem: phones not shown among contacts list

**Is your feature request related to a problem? Please describe.**
I just helped one friend to open his 1st matrix account.

He comes from WhatsApp/Telegram background.

He got surprised that, when going to invite friends, after giving Element access to the address book, he only got listed contacts with emails.

Also noting that something he liked 👍🏼 was the fact he could subscribe without giving any personal info. Kudos for that 😊 (not all was bad hehe).

Due to his messaging background, most of his contacts are just phone numbers, but not seeing those confused him.

**Describe the solution you'd like**
Phone numbers should appear too, with some actionable feature that lets him invite friends via... maybe SMS?

**Describe alternatives you've considered**

1. In my element android app, I have a "Search for contacts on Matrix" button, which doesn't appear on his app. My friend told me that it would make more sense that, while searching for contacts, those with Matrix accounts already appeared there, just like with wa/tg, so I told him to use that button, but it turns out it didn't appear in his app. This confused us also, because I was telling him to use that option.

1. Using the "Invite friends" button, sharing the invite through other means.