Remove unused strings, ref:

bisq-network#4637 (comment)

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

@@ -2832,21 +2832,6 @@ popup.warning.openOfferWithInvalidMakerFeeTx=The maker fee transaction for offer
   Please go to \"Settings/Network info\" and do a SPV resync.\n\
   For further help please contact the Bisq support channel at the Bisq Keybase team.
 
-popup.warning.trade.depositTxNull=The trade with ID ''{0}'' has no deposit transaction set.\n\n\
-  Please restart the application to see if the problem still exists.\n\n\
-  If it does, please open the trade details popup by clicking on the trade ID. Then click on the transaction IDs for \
-  the maker fee transaction and the taker fee transaction to view them on a block explorer. A transaction \
-  that cannot be found in a block explorer is probably an invalid transaction.\n\n\
-  If this happens, please report it in the #support channel on the Bisq Keybase (https://keybase.io/team/bisq). \
-  If your trade fee transaction is invalid, no funds have left your wallet, you can move the trade to failed trades,\
-  and do an SPV resync for your funds to reappear (see how below).\n\n\
-  If your trade fee transaction is valid, the fee amount is lost, and you can make a \
-  request for reimbursement on the support repository on GitHub (https://github.com/bisq-network/support/issues).\n\n\
-  In both cases, please do an SPV resync from the ''Settings/Network'' screen to clean your wallet of any lingering issues!
-
-popup.warning.trade.depositTxNull.moveToFailedTrades=Move to failed trades
-popup.warning.trade.depositTxNull.shutDown=Shut down Bisq
-
 popup.info.securityDepositInfo=To ensure both traders follow the trade protocol, both traders need to pay a security \
 deposit.\n\nThis deposit is kept in your trade wallet until your trade has been successfully completed, and then it's \
 refunded to you.\n\nPlease note: if you're creating a new offer, Bisq needs to be running for another trader to take \