Quoted email replies is now available to every account by default.
Previously this was gated behind the `quoted_email_reply` account-level
feature flag, so accounts needed it toggled on (via Super Admin) before
agents saw the toggle in the reply box.
## How to test
1. Open any conversation on an email inbox.
2. Confirm the **Quote previous email** toggle is visible in the reply
box (and is **not** visible on private notes or non-email channels).
3. Toggle it on, type a reply, and send — the outbound email should
include the quoted prior email below your message.
4. Toggle it off and send another reply — the quoted block should not
appear.
5. The toggle preference should persist per channel type (UI setting),
as before.
6. Verify the toggle works on a brand new account with no feature flags
flipped on (previously it would have been hidden).
## What changed
- Removed all `isFeatureEnabledonAccount(..., QUOTED_EMAIL_REPLY)` gates
from `ReplyBox.vue`, so the toggle and quoted-content behavior are
unconditional on email channels.
- Removed the `QUOTED_EMAIL_REPLY` constant from
`dashboard/featureFlags.js`.
- Marked the flag as `deprecated: true` in `config/features.yml` (kept
the entry in place to preserve FlagShihTzu bit positions on existing
accounts; `deprecated: true` hides it from the Super Admin UI).
- Dropped the now-unnecessary
`account.enable_features('quoted_email_reply')` setup from the message
builder spec.
