Change message saying that remote nodes can only handle online transactions

[dbadol]

Bug description
When using a remote node, the message on the top bar of the wallet says that the "connected node supports online transactions only". That is not correct, Because even with a remote node, offline transactions can be performed.

To Reproduce
Connect the GUI wallet to a remote node and see the displayed message on top of the wallet window. Send some coins to someone via an offline transaction. The process works perfectly, contrary to the displayed message!

Original reason for the message
As explained by @valdok, there is not technical limitation about sending offline transactions through a remote node. The actual limitation is that the remote node cannot automatically scan the blockchain to notify about changes in the users' shielded UTXOs. So when someone sends us coins via offline transaction, our wallet won't be notified (until a rescan is performed).

Expected behaviour
We propose a new message, more precise and closer to reality (while still keeping the sentence short):
"connected node might not show the latest received offline transactions".

Other locations
It's possible that a similar message also appear in other places of the wallet. By instance, the second screenshot below shows such a message when selecting a remote node in the mobile wallet. Those sentence would have to be modified also (by instance: "Random node will not automatically show the latest received offline transactions").

Platform and build

• Windows, Mac, Linux (but also applies to Android or iOS)
• Wallet version 7.5

Screenshots

[dbadol]

I now see that when connected to a remote node (without owner key), the regular addresses proposed by the wallet are always online only. So, in principle, within the normal use of the wallet, it is not actually possible to receive offline transactions (since we cannot provide an offline address!).

Thus, in conclusion: With an remote node we can send offline transactions, but we cannot really receive any (or if we receive any, we won't see it).

Thus, I am adjusting a little bit the proposed sentence for the top message:
"connected node is not compatible with receiving offline transactions".

And for the second message in the screenshots above:
"Random node is not compatible with receiving offline transactions"