fix: Honor "display hash" setting for EIP-191 personal messages

The app exposes a "Always display the transaction or message hash"
setting and the EIP-191 signing path computes the message hash before
launching the review. However, the NBGL personal-message review never
consulted N_storage.displayHash and never added the hash to the review
pairs. Users who explicitly enabled hash display did not actually see
the hash for personal-message signing, reducing their ability to
verify the exact bytes being signed when rendering is ambiguous
(whitespace, encoding differences, long content, hex fallback).

Mirror the transaction-hash flow already used in ui_approve_tx: when
N_storage.displayHash is set, format tmpCtx.messageSigningContext.hash
into strings.common.tx_hash and append it as a second review pair
labelled "Message hash". The setting toggle now applies consistently
to EIP-191 messages, EIP-712 typed data, and transactions.

(cherry picked from commit 8809456597a538d595b50fd5c07e689f0ce6bdf3)