fix: Home's list drops the previous network's rows after a network switch (closes #718)

A network switch left the previous network's rows or failure message in Home's
list until the new network's answer landed. Home now replaces them with
"Loading..." when it first draws on a new network. A redraw on the same network
keeps its rows.

Home, AddressDetail and AddressToken compared the page's network before reading
storage. A switch made in Settings could change the page during that read, and
the answer was still drawn. They now compare after the read, for an answer and
for a failure.

Model: opus-5-5

README.md

@@ -558,7 +558,8 @@ three lines:
 A contract creation has no counterparty. Its last line reads "This transaction
 creates a new contract. It has no recipient." While "Use Blockscout" is off, the
 list shows only the line "No transaction history is shown, because "Use
-Blockscout" is off in Settings."
+Blockscout" is off in Settings." After a network switch, the list shows
+"Loading..." in place of the previous network's rows or failure message.
 
 Transitions: