fix: Show stream is muted correctly
fix: Show stream is muted correctly

Fixes #2433

We were trying to retrieve the `mute` state from the `stream` value
but it is in the `subscription` one.

This also fixes not being able to change the mute state on muted stream.

vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile,vishwesh3/zulip-mobile