Adjust tradeLimitDueAccountAgeRestriction

So that it describes why an account isn't signed (in general) instead of
why it wasn't signed by an arbitrator.

core/src/main/resources/i18n/displayStrings.properties

@@ -381,12 +381,12 @@ offerbook.warning.newVersionAnnouncement=With this version of the software, trad
   For more information on account signing, please see the documentation at https://docs.bisq.network/payment-methods#account-signing.
 
 popup.warning.tradeLimitDueAccountAgeRestriction.seller=The allowed trade amount is limited to {0} because of security restrictions based on the following criteria:\n\
- - The buyer''s account is not at least 60 days old\n\
- - The buyer''s account was not involved in a dispute in which BTC was received (proving that fiat payment from this account occurred) \n\
+ - The buyer''s account has not been signed by an arbitrator or a peer\n\
+ - The time since signing of the buyer''s account is not at least 30 days\n\
  - The payment method for this offer is considered risky for bank chargebacks\n\n{1}
 popup.warning.tradeLimitDueAccountAgeRestriction.buyer=The allowed trade amount is limited to {0} because of security restrictions based on the following criteria:\n\
- - Your payment account is not at least 60 days old\n\
- - Your account was not involved in a dispute in which BTC was received (proving that fiat payment from this account occurred) \n\
+ - Your account has not been signed by an arbitrator or a peer\n\
+ - The time since signing of your account is not at least 30 days\n\
  - The payment method for this offer is considered risky for bank chargebacks\n\n{1}
 
 offerbook.warning.wrongTradeProtocol=That offer requires a different protocol version as the one used in your version of the software.\n\nPlease check if you have the latest version installed, otherwise the user who created the offer has used an older version.\n\nUsers cannot trade with an incompatible trade protocol version.