UI improvements:
- update remaining GUI wallet labels and tooltips from passwords to passphrases
- improve grammar of labels in askpassphrase dialog and WalletController::closeWallet
Backport of Core PR16822 - part 2 of 3
Commit https://github.com/bitcoin/bitcoin/pull/16822/commits/539d9403af956c76ae0149a58c07c71a6b58ac69
Depends on D8006